On February 11, 2024, Diamondback Energy, Inc., a Delaware corporation (“Diamondback,” “we,” “us” or “our”) entered into an Agreement and Plan of Merger, which was amended on March 18, 2024 (as so amended, and as it may be further amended from time to time, the “Merger Agreement”), with Eclipse Merger Sub I, LLC, a Delaware limited liability company and a wholly owned subsidiary of Diamondback (“Merger Sub I”), Eclipse Merger Sub II, LLC, a Delaware limited liability company and a wholly owned subsidiary of Diamondback (“Merger Sub II” and together with Merger Sub I, the “Merger Subs”), Endeavor Manager, LLC, a Texas limited liability company (the “Company Representative”) (solely for purposes of certain sections set forth therein), and Endeavor Parent, LLC, a Texas limited liability company (“Endeavor”).

The Merger Agreement provides that, subject to the terms and conditions set forth therein, Merger Sub I will merge with and into Endeavor (the “First Merger”), with Endeavor surviving the First Merger and becoming a wholly owned subsidiary of Diamondback (the “First Surviving Company”). Immediately following the First Merger, the First Surviving Company will merge with and into Merger Sub II (the “Second Merger”, and together with the First Merger, the “Merger”), with Merger Sub II surviving the Second Merger and continuing (immediately following the Second Merger) as a wholly owned subsidiary of Diamondback (the “Surviving Company”). As a result of the Merger, Diamondback will acquire 100% of the equity interests in Endeavor (the “Endeavor Interests”).

If the Merger is completed, pursuant to and subject to the terms and conditions of the Merger Agreement, the Endeavor Interests will be converted into the right to receive, in the aggregate, (i) cash consideration of $8.0 billion, subject to adjustments according to the terms of the Merger Agreement (the “Cash Consideration”), and (ii) 117,267,069 shares of common stock, par value $0.01 per share of Diamondback (the “common stock” and such consideration, the “Common Stock Consideration” and together with the Cash Consideration, the “Merger Consideration”).

Immediately following the closing of the Merger and based on the estimated number of shares of common stock outstanding immediately prior to the execution of the Merger Agreement, we estimate that the existing Diamondback stockholders will own approximately 60.5% of the combined company, and holders of the Endeavor Interests will own approximately 39.5% of the combined company.

In connection with the Merger, you are cordially invited to a special meeting of stockholders of Diamondback (the “special meeting”), which will be held in person. At the special meeting, Diamondback stockholders will be asked to consider and vote upon (i) a proposal to approve the issuance of 117,267,069 shares of common stock in connection with the Merger (the “Stock Issuance” and such proposal, the “Stock Issuance Proposal”), (ii) a proposal to adopt an amendment to the Second Amended and Restated Certificate of Incorporation of Diamondback (the “Charter”) to increase the total number of authorized shares of common stock under the terms of the Charter from 400 million shares to 800 million shares of common stock (the “Charter Amendment” and such proposal, the “Charter Amendment Proposal”) and (iii) a proposal to adjourn the special meeting to a later date or time if necessary or appropriate, including to solicit additional proxies if there are not sufficient votes cast at the special meeting to approve the Stock Issuance Proposal (the “Adjournment Proposal”).

For more information concerning the special meeting, the Merger Agreement and the transactions contemplated thereby, including the Merger, the Stock Issuance and the Charter Amendment, please review the accompanying proxy statement, the copy of the Merger Agreement attached as Annex A-1 to the proxy statement and the copy of the Letter Agreement, amending the Merger Agreement (the “Letter Agreement”), attached as Annex A-2 to this proxy statement.

The Board of Directors of Diamondback (the “Board”), after considering the factors more fully described in the enclosed proxy statement, unanimously: (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment are fair to and in the best interests of Diamondback and the holders of Diamondback common stock; (ii) approved and declared advisable the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; (iii) resolved to recommend that the holders of Diamondback common stock approve the Stock Issuance Proposal and the Charter Amendment Proposal; (iv) approved the execution, delivery and performance by Diamondback of the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; and (v) authorized and approved the submission of the Stock Issuance Proposal and the Charter Amendment Proposal for approval by the holders of Diamondback common stock.

The Board unanimously recommends a vote “FOR” the Stock Issuance Proposal, “FOR” the Charter Amendment Proposal and “FOR” the Adjournment Proposal.

Your vote is important. We cannot complete the Merger unless the Stock Issuance Proposal is approved by the holders of Diamondback common stock. Whether or not you plan to attend the special meeting and regardless of the number of shares of Diamondback common stock you own, your careful consideration and vote on the proposals to be presented at the special meeting is important, and we encourage you to vote promptly. The failure to vote will have the same effect as a vote “AGAINST” the Charter Amendment Proposal, but, assuming a quorum is present, will have no effect on the approval of the Stock Issuance Proposal or the Adjournment Proposal.

After reading the accompanying proxy statement, please make sure to vote your shares of common stock promptly (1) by completing, signing and dating the accompanying proxy card and returning it in the enclosed prepaid envelope, (2) by telephone or (3) through the internet by following the instructions on the accompanying proxy card. Instructions regarding all three methods of voting are provided on the proxy card. If you hold shares of common stock through an account with a bank, broker, trust or other nominee, please follow the instructions you receive from your bank, broker, trust or other nominee to vote your shares.

Your support of and interest in Diamondback is sincerely appreciated. We look forward to the successful combination of Diamondback and Endeavor.

Neither the United States Securities and Exchange Commission nor any state securities regulatory agency has approved or disapproved the transactions described herein, or passed upon the adequacy or accuracy of the disclosure in this document. Any representation to the contrary is a criminal offense.

The accompanying proxy statement is dated [•], 2024 and is first being mailed to Diamondback stockholders on or about [•], 2024.

A special meeting of stockholders (the “special meeting”) of Diamondback Energy, Inc., a Delaware corporation (“Diamondback,” “we,” “us” or “our”), will be held in person on [   ], 2024, at [   ] Central Time at Petroleum Club of Midland, 501 West Wall Street, Midland, TX 79701.

At the special meeting, you will be asked to consider and vote on the following proposals:

Stockholders of record at the close of business on [   ], 2024 (the “record date”) are entitled to notice of, and to vote at, the special meeting and any adjournments or postponements thereof.

The Stock Issuance Proposal and the Adjournment Proposal requires the affirmative vote of the holders of a majority of votes cast by Diamondback stockholders at the special meeting, assuming a quorum is present. The Charter Amendment Proposal requires the affirmative vote of the holders of a majority of the outstanding shares of common stock.

For more information concerning the special meeting, the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment, please review the accompanying proxy statement, the copy of the Merger Agreement attached as Annex A-1 to the proxy statement and the copy of the Letter Agreement, amending the Merger Agreement, attached as Annex A-2 to this proxy statement.

The Board carefully reviewed and considered the terms and conditions of the Merger Agreement, and the transactions contemplated thereby, including the Stock Issuance and the Charter Amendment. By a unanimous vote, the Board: (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment are fair to and in the best interests of Diamondback and the holders of Diamondback common stock; (ii) approved and declared advisable the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; (iii) resolved to recommend that the holders of Diamondback common stock approve the Stock Issuance Proposal and the Charter Amendment Proposal; (iv) approved the execution, delivery and performance by Diamondback of the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; and (v) authorized and approved the submission of the Stock Issuance Proposal and the Charter Amendment Proposal for approval by the holders of Diamondback common stock.

The Board unanimously recommends that you vote “FOR” the Stock Issuance Proposal, “FOR” the Charter Amendment Proposal and “FOR” the Adjournment Proposal.

To assure that your shares of common stock are represented at the special meeting, regardless of whether you plan to attend the special meeting, please fill in your vote, sign and mail the enclosed proxy card as soon as possible.

Alternatively, you may vote by telephone or through the internet. Instructions regarding each of the methods of voting are provided on the enclosed proxy card. Your proxy is being solicited by the board of directors of Diamondback.

If you have any questions about the Merger, the special meeting or how to submit your proxy, or if you need additional copies of this proxy statement or the enclosed proxy card, please write to Corporate Secretary, Diamondback Energy, Inc., 500 West Texas Ave, Suite 100, Midland, TX 79701.

If you fail to return your proxy, vote by telephone or through the internet or attend the special meeting in person, your shares will not be counted for purposes of determining whether a quorum is present at the special meeting and will have the same effect as a vote “AGAINST” the Charter Amendment Proposal, but, assuming a quorum is present, will have no effect on the approval of the Stock Issuance Proposal or the Adjournment Proposal.

The following questions and answers are intended to briefly address some commonly asked questions regarding the special meeting and the matters that are the subject of the special meeting. These questions and answers do not address all questions that may be important to you as a Diamondback stockholder. Please refer to the more detailed information contained elsewhere in this proxy statement, the Annexes to this proxy statement and the documents referred to in this proxy statement.

Certain information in this proxy statement constitutes “forward-looking statements” within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which involve risks, uncertainties, and assumptions. All statements, other than statements of historical fact, including statements regarding our: future performance; business strategy; future operations (including drilling plans and capital plans); estimates and projections of revenues, losses, costs, expenses, returns, cash flow, and financial position; reserve estimates and our ability to replace or increase reserves; anticipated timing, objectives and benefits of the Merger and other strategic transactions (including acquisitions and divestitures); and plans and objectives of management (including plans for future cash flow from operations and for executing environmental strategies) are forward-looking statements. When used in this report, the words “aim,” “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “forecast,” “future,” “guidance,” “intend,” “may,” “model,” “outlook,” “plan,” “positioned,” “potential,” “predict,” “project,” “seek,” “should,” “target,” “will,” “would,” and similar expressions (including the negative of such terms) as they relate to Diamondback are intended to identify forward-looking statements, although not all forward-looking statements contain such identifying words. Although we believe that the expectations and assumptions reflected in our forward-looking statements are reasonable as and when made, they involve risks and uncertainties that are difficult to predict and, in many cases, beyond our control. Accordingly, forward-looking statements are not guarantees of future performance and our actual outcomes could differ materially from what we have expressed in our forward-looking statements. Factors that could cause our actual results to differ materially from these forward-looking statements may include, without limitation:

The foregoing list of factors should not be construed as exhaustive. Diamondback can give no assurance that the expectations expressed or implied in the forward-looking statements contained herein will be attained. The statements made in this proxy statement are current as of the date of this proxy statement only. Diamondback undertakes no obligation to publicly update or revise any forward-looking statements or any other information contained herein, whether as a result of new information, future events or otherwise, except as required by law. Readers are cautioned not to place undue reliance on these forward-looking statements that speak only as of the date hereof.

In addition to the other information contained in or incorporated by reference herein, including the matters addressed in the section entitled “Cautionary Statement Regarding Forward-Looking Statements,” Diamondback stockholders should carefully consider the following risks relating to the Merger and combined company before deciding how to vote with respect to the Stock Issuance Proposal, the Charter Amendment Proposal and the Adjournment Proposal to be considered and voted on at the special meeting. You should also read and consider the risks associated with each of the businesses of Diamondback and Endeavor because these risks will also affect the combined company. The risks associated with the business of Diamondback can be found in Diamondback’s Annual Report on Form 10-K for the year ended December 31, 2023 under the heading “Risk Factors” and may be updated or supplemented in Diamondback’s subsequently filed Quarterly Reports on Form 10-Q or Current Reports on Form 8-K. Such risk factors are incorporated by reference into this proxy statement. Risks associated with the business of Endeavor can be found below in the section entitled “Risks Relating to Endeavor.” Diamondback stockholders are also urged to carefully consider all of the information included or incorporated by reference in this proxy statement, which are listed in the section entitled “Where You Can Find More Information.”

The Merger is subject to a number of conditions to closing as specified in the Merger Agreement. These closing conditions include, among others, including (i) the receipt of the Diamondback Stockholder Approval, (ii) the Diamondback common stock to be issued as Merger Consideration having been authorized for listing on Nasdaq, (iii) the expiration or termination of the waiting period under the HSR Act, (iv) the absence of any injunction, order, decree or law preventing, prohibiting or making illegal the consummation of the First Merger and, (v) with respect to each party, (A) the accuracy of the other party’s representations and warranties, subject to specified materiality qualifications, (B) compliance by the other party with its covenants in the Merger Agreement in all material respects, and (C) the absence of a “Material Adverse Effect” (as defined in the Merger Agreement) with respect to the other party since the date of the Merger Agreement with respect to the other party since the date of the Merger Agreement that is continuing, and (vi) in the case of Endeavor, the receipt of an opinion of tax counsel that the Merger will qualify as a “reorganization” within the meaning of Section 368(a) of the Code.

No assurance can be given that the Diamondback Stockholder Approval and regulatory clearance will be obtained or that the other required conditions to Closing will be satisfied. Even if regulatory clearance is obtained, no assurance can be given as to the terms, conditions and timing of such clearance, including whether any required conditions will materially adversely affect the combined company following Closing. Any delay in completing the Merger could cause the combined company not to realize, or to be delayed in realizing, some or all of the benefits that Diamondback and Endeavor expect to achieve if the Merger is successfully completed within its expected time frame. Diamondback can provide no assurance that these conditions will not result in the abandonment or delay of the Merger. The occurrence of any of these events individually or in combination could have a material adverse effect on Diamondback’s results of operations and the trading price of the common stock.

If the Merger is not completed by the Outside Date, either Diamondback or Endeavor may choose not to proceed with the Merger by terminating the Merger Agreement, and the parties can mutually decide to terminate the Merger Agreement at any time, before or after the Diamondback Stockholder Approval is received. In addition, Diamondback and Endeavor may elect to terminate the Merger Agreement in certain other circumstances as further detailed in the section entitled “The Merger Agreement—Termination.”

If the Merger is not completed for any reason, including as a result of a failure to obtain the Diamondback Stockholder Approval, Diamondback’s ongoing business may be adversely affected and, without realizing any of the expected benefits of having completed the Merger, Diamondback would be subject to a number of risks, including the following:

Diamondback is also required to pay Endeavor a termination fee of $1,400,000,000 if the Merger Agreement is terminated by (i) Endeavor because the Board has made an adverse recommendation change or (ii) if either party terminates the Merger Agreement because of the failure to receive the Diamondback Stockholder Approval and, immediately prior to the failed vote, Endeavor would have been entitled to terminate the Merger Agreement because the Board had made an adverse recommendation change. If the Merger Agreement is terminated under certain specified circumstances and, within 12 months following such termination, Diamondback consummates or enters into an alternative transaction, Diamondback will be required to pay the termination fee to Endeavor. Additionally, if the Merger Agreement is terminated because the of the failure to receive the Diamondback Stockholder Approval and the termination fee is not payable in connection with such termination, Diamondback is required to reimburse Endeavor for its transaction related expenses, subject to a cap of $260,000,000. The payment of this expense reimbursement will reduce any termination fee that is subsequently payable by Diamondback. For more information, see the section entitled “The Merger Agreement—Termination Fees.”

Whether or not the Merger is completed, the announcement and pendency of the Merger could cause disruptions to Diamondback’s business, including:

Diamondback has and will continue to divert significant management resources in an effort to complete the Merger and is subject to restrictions contained in the Merger Agreement on the conduct of its business. If the Merger is not completed, Diamondback will have incurred significant costs, including the diversion of management resources, for which Diamondback will have received little or no benefit.

Pursuant to the Merger Agreement, the Cash Consideration to be paid in connection with the Merger is subject to certain adjustments, as more fully described in the section entitled “The Merger Agreement—The Merger Consideration.”

Because certain of the individual items forming the adjustments to be made to the Cash Consideration are not knowable with full certainly by Diamondback prior to the Merger, the final Cash Consideration paid by Diamondback may be materially higher than the base cash consideration of $8.0 billion. If the Cash Consideration is materially higher than expected, the value of the Merger to Diamondback and its current stockholders may be materially less than was anticipated upon Diamondback’s entry into the Merger Agreement.

The Merger Agreement contains provisions that make it more difficult for Diamondback to enter into another transaction other than the one currently contemplated by the Merger Agreement. Specifically, Diamondback has agreed not to, among other restrictions, solicit, initiate, endorse or knowingly encourage or knowingly facilitate any inquiry, proposal or offer that constitutes or could reasonably lead to an acquisition proposal, enter into, continue or otherwise participate in any discussions or negotiations regarding, or furnish to any person any non-public information or data with respect to, or otherwise cooperate in any way with, any acquisition proposal or any inquiry, proposal or offer that constitutes or could reasonably be expected to lead to any acquisition proposal, take any action to exempt any person from the restrictions on “business combinations” contained in any applicable state takeover statute or otherwise cause such restrictions not to apply, cause or permit itself or any of its subsidiaries to enter into, or publicly declare advisable or publicly propose to enter into, any letter of intent, memorandum of understanding, agreement in principle, acquisition agreement, merger agreement, option agreement, joint venture agreement, partnership agreement or other contract, in each case constituting or related to any acquisition proposal or approve, authorize or publicly announce any intention to do any of the foregoing.

Diamondback is required to pay Endeavor a termination fee of $1,400,000,000 if the Merger Agreement is terminated by (i) Endeavor because the Board has made an adverse recommendation change or (ii) if either party terminates the Merger Agreement because of the failure to receive the Diamondback Stockholder Approval and, immediately prior to the failed vote, Endeavor would have been entitled to terminate the Merger Agreement because the Board had made an adverse recommendation change. If the Merger Agreement is terminated under certain specified circumstances and, within 12 months following such termination, Diamondback consummates or enters into an alternative transaction, Diamondback is required to pay the termination fee to Endeavor. Additionally, if the Merger Agreement is terminated because the of the failure to receive the Diamondback Stockholder Approval and the termination fee is not payable in connection with such termination, Diamondback will be required to reimburse Endeavor for its transaction related expenses, subject to a cap of $260,000,000.

The foregoing may discourage a third party that might have an interest engaging in a transaction with Diamondback from considering or proposing a transaction, even if that party were prepared to propose a transaction that would present greater value to Diamondback and its stockholders than does the Merger.

The unaudited pro forma combined financial statements and unaudited forecasted financial information contained in this proxy statement is presented for illustrative purposes only, contains a variety of adjustments, assumptions and preliminary estimates and does not represent the actual financial position or results of operations of Diamondback or Endeavor prior to the Merger or that of the combined company following the Merger for several reasons. Specifically, the unaudited pro forma combined financial statements do not reflect the effect of any integration costs or any changes in Diamondback’s capital structure following the completion of the Merger.

For additional information, see the section entitled “Unaudited Pro Forma Combined Financial Statements.” In addition, the Merger and post-merger integration process may give rise to unexpected liabilities and costs, including costs associated with the defense and resolution of transaction-related litigation or other claims. Unexpected delays in completing the Merger or in connection with the post-merger integration process may significantly increase the related costs and expenses incurred by Diamondback. The actual financial positions and results of operations of Diamondback and Endeavor prior to the Merger and that of the combined company following the Merger may be different, possibly materially, from the unaudited pro forma combined financial statements or forecasted financial information included in this proxy statement. In addition, the assumptions used in preparing the unaudited pro forma combined financial statements and forecasted financial information included in this proxy statement may not prove to be accurate and may be affected by other factors. Any significant changes in the market price of Diamondback common stock may cause a significant change in the purchase price used for Diamondback’s accounting purposes and the unaudited pro forma financial statements contained in this proxy statement.

The Board received an opinion from Diamondback’s financial advisor in connection with the signing of the Merger Agreement. Please refer to the section entitled “The Merger—Opinion of Diamondback’s Financial Advisor” for additional information. However, Diamondback has not obtained any updated opinion from its financial advisor as of the date of this proxy statement. Changes in the operations and prospects of Diamondback or Endeavor, general market and economic conditions and other factors that may be beyond the control of Diamondback, and on which the financial advisor’s opinion were based, may significantly alter the value of Diamondback or Endeavor or the value of their respective equity by the time the Merger is completed, and thus the fairness of the Merger Consideration, from a financial point of view, to Diamondback. The opinion does not speak as of the time the Merger will be completed or as of any date other than the date of such opinion.

Securities class action lawsuits and derivative lawsuits are often brought against publicly listed companies that have entered into merger agreements. Even if the lawsuits are without merit, defending against these claims can result in substantial costs and divert management time and resources. An adverse judgment could result in monetary damages, which could have a negative impact on Diamondback.

Lawsuits related to the Merger may be filed against Diamondback and its affiliates, directors and officers. If dismissals are not obtained or a settlement is not reached, these lawsuits could prevent or delay completion of Merger and/or result in substantial costs to Diamondback. These lawsuits could seek, among other things, injunctive relief or other equitable relief, including a request to rescind parts of the Merger Agreement already implemented and to otherwise enjoin the parties from consummating the Merger. One of the conditions to the Merger is that there is no injunction, order, decree or law preventing, prohibiting or making illegal the consummation of the First Merger. For a detailed discussion of the terms and conditions of the Merger, see the section entitled “The Merger Agreement—Conditions to the Merger.” Consequently, if a plaintiff is successful in obtaining an injunction prohibiting completion of the Merger, then that injunction may delay or prevent the Merger from being completed, which may adversely affect Diamondback’s business, financial position and results of operation. There can be no assurance that any of the defendants will be successful in the outcome of any pending or any potential future lawsuits. The defense or settlement of any lawsuit or claim that remains unresolved at the time the Merger is completed may adversely affect Diamondback’s ongoing business, financial condition, results of operations and cash flows.

The success of the Merger will depend on, among other things, the ability of the two companies to combine their businesses in a manner that facilitates growth opportunities and realizes expected cost savings. The combined company may encounter difficulties in integrating Diamondback’s and Endeavor’s businesses and

realizing the anticipated benefits of the Merger. The combined company must achieve the anticipated improvement in free cash flow generation and returns and achieve the planned cost savings without adversely affecting current revenues and operations. If the combined company is not able to successfully achieve these objectives, the anticipated benefits of the Merger may not be realized fully, or at all, or may take longer to realize than expected.

The Merger involves the combination of two companies which currently operate, and until the completion of the Merger will continue to operate, as independent companies. There can be no assurances that the businesses can be integrated successfully. It is possible that the integration process could result in the loss of key employees from both companies; the loss of commercial and vendor partners; the disruption of Diamondback’s, Endeavor’s or both companies’ ongoing businesses; inconsistencies in standards, controls, procedures and policies; unexpected integration issues; higher than expected integration costs and an overall post-completion integration process that takes longer than originally anticipated. The combined company will be required to devote management attention and resources to integrating its business practices and operations, and prior to the Merger, management attention and resources will be required to plan for such integration. An inability to realize the full extent of the anticipated benefits of the Merger and the other transactions contemplated by the Merger Agreement, as well as any delays encountered in the integration process, could have an adverse effect upon the revenues, level of expenses and operating results of the combined company, which may adversely affect the value of the common stock of the combined company. In addition, the actual integration may result in additional and unforeseen expenses, and the anticipated benefits of the integration plan may not be realized. There are a large number of processes, policies, procedures, operations and technologies and systems that must be integrated in connection with the Merger and the integration of Endeavor’s business. Although Diamondback expects that the elimination of duplicative costs, strategic benefits, and additional income, as well as the realization of other efficiencies related to the integration of the business, may offset incremental transaction and Merger-related costs over time, any net benefit may not be achieved in the near term or at all. If Diamondback and Endeavor are not able to adequately address integration challenges, Diamondback may be unable to successfully integrate operations or realize the anticipated benefits of the integration of the two companies.

Following completion of the Merger, Diamondback’s success will depend, in part, on its ability to manage its expansion, which poses numerous risks and uncertainties, including the need to integrate the operations and business of Endeavor into its existing business in an efficient and timely manner, to combine systems and management controls and to integrate relationships with industry contacts and business partners.

The Merger will be accounted for as an acquisition by Diamondback in accordance with accounting principles generally accepted in the United States (“GAAP”). Under the acquisition method of accounting, the assets and liabilities of Endeavor and its subsidiaries will be recorded, as of completion, at their respective fair values and added to those of Diamondback. The reported financial condition and results of operations of Diamondback for periods after completion of the Merger will reflect Endeavor balances and results after completion of the Merger but will not be restated retroactively to reflect the historical financial position or results of operations of Endeavor and its subsidiaries for periods prior to the Merger. For additional information, see the section entitled “Unaudited Pro Forma Combined Financial Statements.”

Under the acquisition method of accounting, the total purchase price will be allocated to Endeavor’s tangible assets and liabilities and identifiable intangible assets based on their fair values as of the date of completion of the Merger. The excess of the purchase price over those fair values will be recorded as goodwill. Diamondback expects that the Merger may result in the creation of goodwill based upon the application of the acquisition method of accounting. To the extent goodwill or intangibles are recorded and the values become impaired, the combined company may be required to recognize material non-cash charges relating to such impairment. The combined company’s operating results may be significantly impacted from both the impairment and the underlying trends in the business that triggered the impairment.

Because shares of common stock will be issued in the Merger, it is possible that, although Diamondback currently expects the Merger to be accretive to earnings per share, the Merger may be dilutive to Diamondback’s earnings per share, which could negatively affect the market price of the common stock.

Diamondback will issue 117,267,069 shares of common stock in the Merger. The issuance of these new shares of common stock could have the effect of depressing the market price of the common stock, through dilution of earnings per share or otherwise. Any dilution of, or delay of any accretion to, Diamondback’s earnings per share could cause the price of shares of common stock to decline or to increase at a lower rate than anticipated.

If the Merger is consummated, Diamondback will issue 117,267,069 shares of common stock to the holders of the Endeavor Interests. At Closing, Diamondback will enter into the Stockholders Agreement with the Endeavor Stockholders that will, among other things, provide the Endeavor Stockholders with certain shelf, demand and piggyback registration rights. While the Endeavor Stockholders will be subject to a lock-up with respect to 90% of the shares of common stock issued in the Merger for a period of six months following the Closing, the lock-up will apply to only 66.6% and 33.3% of the shares issued in the Merger following the six- and 12-month anniversaries, respectively, of the Closing and will terminate entirely following the 18-month anniversary of the Closing. The Endeavor Stockholders may decide not to hold their shares of common stock that they will receive in the Merger, and may instead decide to reduce their investment in Diamondback. Such sales of common stock or the perception that these sales may occur, could have the effect of depressing the market price for the common stock.

The Stock Issuance will result in significant dilution of the ownership percentage of Diamondback of current Diamondback stockholders following the Merger. Based on the estimated number of shares of common stock outstanding immediately prior to the execution of the Merger Agreement, current Diamondback stockholders are expected to own approximately 60.5% of Diamondback following the Merger, whereas the former holders of the Endeavor Interests are expect to own approximately 39.5% of Diamondback following the Merger. Consequently, current Diamondback stockholders will, as a general matter, have less influence over the management and policies of Diamondback following the Merger as compared to their influence over Diamondback prior to the Merger.

In addition to the significant common stock ownership the Endeavor Stockholders will have following the completion of the Merger, the Stockholders Agreement will provide the Endeavor Stockholders with the right to propose for nomination four directors for election to the Board if they beneficially own at least 25% of the outstanding shares of our common stock, two directors if they beneficially own at least 20% but less than 25% of the outstanding shares of our common stock, and one director if they beneficially own at least 10% but less than 20% of the outstanding shares of our common stock, in each case subject to certain qualification requirements for such directors. Diamondback will not be permitted to take certain actions without the consent of the holders of a majority of the shares of common stock held by the Endeavor Stockholders. The Endeavor Stockholders’ level of ownership and influence may make some transactions (such as those involving mergers, material share issuances or changes in control) more difficult or impossible without the support of the Endeavor Stockholders, which in turn could adversely affect the market price of the shares of common stock or prevent Diamondback stockholders from realizing a premium over the market price for their shares of common stock. The interests of the Endeavor Stockholders may conflict with the interests of Diamondback’s other stockholders.

Each of Diamondback and Endeavor has incurred, and expects to continue to incur, a number of non-recurring costs associated with negotiating and completing the Merger, combining the operations of the

two companies and achieving desired synergies. These fees and costs have been, and will continue to be, substantial. The substantial majority of non-recurring expenses will consist of transaction costs related to the Merger and include, among others, employee retention costs, fees paid to financial, legal and accounting advisors, severance and benefit costs and filing fees.

Diamondback and Endeavor will also incur transaction fees and costs related to formulating and implementing integration plans, including facilities and systems consolidation costs and employment-related costs. Diamondback and Endeavor will continue to assess the magnitude of these costs, and additional unanticipated costs may be incurred in the merger and the integration of the two companies’ businesses. Although Diamondback and Endeavor each expect that the elimination of duplicative costs, as well as the realization of other efficiencies related to the integration of the businesses, should allow the combined company to offset integration-related costs over time, this net benefit may not be achieved in the near term, or at all.

The costs described above, as well as other unanticipated costs and expenses, could have a material adverse effect on the financial condition and operating results of Diamondback following the completion of the Merger. Many of these costs will be borne by Diamondback even if the Merger is not completed.

If Diamondback stockholders do not approve the Charter Amendment Proposal, the combined company will continue to have 400 million authorized shares of common stock. As of the date of the Merger Agreement, there were approximately 178 million shares of common stock outstanding. Diamondback anticipates issuing or reserving for issuance 117,267,069 shares of common stock in connection with the Stock Issuance. If Diamondback stockholders do not approve the Charter Amendment Proposal, the combined company would have less than 105 million authorized shares of common stock available for issuance following the completion of the Merger and would be limited in its ability to, among other things, raise or otherwise utilize equity by issuing additional shares of common stock or utilize equity in other transactions such as business combinations unless it first obtains approval from its stockholders to amend the Charter to increase the number of authorized shares of common stock. No assurance can be given that the combined company’s stockholders will approve an increase in the number of authorized shares of common stock and, even if they approve such an increase, that the combined company will be able to raise or otherwise utilize equity by issuing additional shares of common stock. If the combined company is unable to raise or otherwise utilize equity by issuing additional shares of common stock, it could have a material adverse effect on the combined company’s ongoing business, results of operations, cash flows and financial position and ability to pursue transactions which the combined company may believe are in the best interests of its stockholders.

Diamondback will incur debt to finance all or a portion of the Cash Consideration paid in connection with the Merger and to repay certain existing indebtedness of Endeavor and its subsidiaries. The increased level of debt in connection with this debt financing could have negative consequences on Diamondback and the combined company, including, among other things, (i) requiring Diamondback, and the combined company, to dedicate a larger portion of cash flow from operations to servicing and repayment of the debt, (ii) reducing funds available for strategic initiatives and opportunities, working capital and other general corporate needs, (iii) limiting Diamondback’s and the combined company’s ability to incur additional indebtedness, which could restrict flexibility to react to changes in the combined company’s business, its industry and economic condition following the Merger, and (iv) placing Diamondback, and the combined company, at a competitive disadvantage compared to competitors that have less debt.

Because Diamondback and Endeavor operate similar businesses in similar industries, many of the risks relating to Diamondback and its business disclosed in Diamondback’s filings with the SEC are applicable to Endeavor and its business as well. Accordingly, this section should be read in conjunction with the risks relating to Diamondback and its business disclosed in Diamondback’s Annual Report on Form 10-K for the fiscal year ended December 31, 2023, subsequent Quarterly Reports on Form 10-Q and other filings with the SEC.

Endeavor has engaged in, and expects to continue to engage, in related party transactions involving Mr. Stephens, Endeavor’s Chairman and the sole member of Endeavor Manager, and other companies that he controls. For example, in 2023 Endeavor paid approximately $325 million to companies controlled by Mr. Stephens for various goods and services provided to Endeavor, including well completion services, provided by Advanced Stimulation Technologies, Inc. and natural gas gathering and oilfield services provided by ACME Energy Services, Inc.; and Endeavor received approximately $729 million in revenue from Oasis Transportation and Marketing Corporation, a company that is majority owned by Mr. Stephens, in connection with the transportation and sale of Endeavor’s crude oil. Because Mr. Stephens controls these affiliated companies, Endeavor’s existing arrangements with these companies may not be on terms and conditions as favorable to Endeavor as in comparable transactions negotiated at arm’s-length with third parties.

Endeavor’s hedging transactions expose Endeavor to risk of financial loss if a counterparty fails to perform under a derivative contract. The majority of Endeavor’s counterparties are lenders under its revolving credit facility and have investment grade ratings. However, the risk of counterparty non-performance is of particular concern given the disruptions that have occurred in the financial markets and the significant decline in oil, natural gas and NGL prices and the increase in electricity costs, each of which could lead to sudden changes in a counterparty’s liquidity, and impair their ability to perform under the terms of the derivative contract. Endeavor is unable to predict sudden changes in a counterparty’s creditworthiness or ability to perform. Even if Endeavor does accurately predict sudden changes, its ability to negate the risk may be limited depending upon market conditions. Furthermore, the bankruptcy of one or more of its hedge providers or some other similar proceeding or liquidity constraint, might make it unlikely that Endeavor would be able to collect all or a significant portion of amounts owed to Endeavor by the distressed entity or entities. During periods of falling commodity prices, Endeavor’s hedge receivable positions increase, which increases its exposure. If the creditworthiness of its counterparties deteriorates and results in their non-performance, Endeavor could incur a significant loss.

The marketability of Endeavor’s production depends in part upon the availability and capacity of oil and natural gas gathering and gas processing systems, pipelines and other transportation facilities owned by third parties. Transportation space on the gathering systems and pipelines Endeavor utilizes is occasionally limited or unavailable due to repairs or improvements to facilities or due to space being utilized by other companies that have priority transportation agreements. Lack of available capacity has historically resulted in larger regional price differentials. Additionally, new fields may require the construction of gathering systems and other transportation facilities. These facilities may require Endeavor to spend significant capital that would otherwise be spent on drilling. The availability of markets is beyond Endeavor’s control. If market factors dramatically change, the impact on Endeavor’s revenues could be substantial and could adversely affect Endeavor’s ability to produce and market oil, natural gas and NGL. Endeavor’s access to transportation options can also be affected by U.S. federal and state regulation of oil and natural gas production and transportation, general economic conditions and changes in supply and demand.

As of December 31, 2023, Endeavor carried unproved oil and natural gas property costs of $176 million. GAAP requires periodic evaluation of these costs on a project-by-project basis. These evaluations are affected by the results of exploration activities, hydrocarbon price outlooks, planned future sales or expirations of all or a portion of these leases and the contracts and permits relevant to such projects. If the quantity of potential reserves determined by such evaluations is not sufficient to fully recover the costs invested in each project, Endeavor will recognize non-cash charges in future periods.

As of December 31, 2023, Endeavor maintained operational control of approximately 91% of the PV-10 of its proved reserves. Endeavor has limited control over properties which it does not operate or does not otherwise control operations. If Endeavor does not operate or otherwise control the properties in which it owns an interest, Endeavor does not have control over normal operating procedures, expenditures or future development of the underlying properties. The failure of an operator of Endeavor’s wells to adequately perform operations, an operator’s financial difficulties, including the result of price volatility or an operator’s breach of the applicable agreements could reduce Endeavor’s production and revenues. The success and timing of Endeavor’s drilling and development activities on properties operated by others, therefore, depends upon a number of factors outside of Endeavor’s control, including the operator’s timing and amount of capital expenditures, expertise and financial resources, inclusion of other participants in drilling wells and use of technology.

Diamondback Energy, Inc. is an independent oil and natural gas company focused on the acquisition, development, exploration and exploitation of unconventional, onshore oil and natural gas reserves in the Permian Basin in West Texas. This basin, which is one of the major producing basins in the United States, is characterized by an extensive production history, a favorable operating environment, mature infrastructure, long reserve life, multiple producing horizons, enhanced recovery potential and a large number of operators. Diamondback reports operations in one reportable segment, the upstream segment.

Diamondback’s activities are primarily focused on horizontal development of the Spraberry and Wolfcamp formations of the Midland Basin and the Wolfcamp and Bone Spring formations of the Delaware Basin, both of which are part of the larger Permian Basin in West Texas and New Mexico. These formations are characterized by a high concentration of oil and liquids rich natural gas, multiple vertical and horizontal target horizons, extensive production history, long-lived reserves and high drilling success rates.

As of December 31, 2023, Diamondback’s total acreage position in the Permian Basin was approximately 607,877 gross (493,769 net) acres, which consisted primarily of 428,324 gross (349,707 net) acres in the Midland Basin and 174,828 gross (143,742 net) acres in the Delaware Basin. In addition, Diamondback’s publicly traded subsidiary Viper Energy, Inc. (“Viper”), owns mineral interests primarily in the Permian Basin. Diamondback owns approximately 56% of Viper’s outstanding shares of common stock.

As of December 31, 2023, Diamondback’s estimated proved oil and natural gas reserves were 2,177,761 MBOE (which includes estimated reserves of 179,249 MBOE attributable to the mineral interests owned by Viper). As of December 31, 2023, approximately 69% are classified as proved developed producing. Proved undeveloped, or PUD, reserves included in this estimate are from 802 gross (719 net) horizontal well locations in which we have a working interest. As of December 31, 2023, Diamondback’s estimated proved reserves were approximately 53% oil, 23% natural gas and 24% natural gas liquids.

Diamondback’s principal executive offices are located at 500 West Texas Ave, Suite 100, Midland, TX 79701 and its telephone number is (432) 221-7400. Diamondback’s common stock is listed on Nasdaq under the trading symbol “FANG.”

For additional information about Diamondback and its subsidiaries, see the documents incorporated by reference in this proxy statement in the section entitled “Where You Can Find More Information.”

Eclipse Merger Sub I, LLC, a Delaware limited liability company, is a direct, wholly owned subsidiary of Diamondback and was formed solely for the purpose of effecting the First Merger. It has not conducted any activities other than those incidental to its formation and the matters contemplated by the Merger Agreement. Its principal executive offices are located at c/o Diamondback Energy, Inc. 500 West Texas Ave, Suite 100, Midland, TX 79701 and its telephone number is (432) 221-7400.

Eclipse Merger Sub II, LLC, a Delaware limited liability company, is a direct, wholly owned subsidiary of Diamondback and was formed solely for the purpose of effecting the Second Merger. It has not conducted any activities other than those incidental to its formation and the matters contemplated by the Merger Agreement. Its principal executive offices are located at c/o Diamondback Energy, Inc. 500 West Texas Ave, Suite 100, Midland, TX 79701 and its telephone number is (432) 221-7400.

Endeavor Parent, LLC, a Texas limited liability company, is a privately held oil and natural gas company engaged in oil and liquids-rich natural gas acquisition, development, exploitation and exploration in the Permian Basin of West Texas. Endeavor’s core properties are located in the Midland Basin, a sub-basin of the Permian Basin, where it holds approximately 453,000 gross (345,000 net) acres, located almost entirely on state and private lands, as of December 31, 2023. The majority of Endeavor’s acreage is located on large, contiguous acreage blocks in the core of the Midland Basin, across primarily Midland, Martin, Howard, Glasscock, Upton and Reagan Counties, Texas.

Endeavor’s principal executive offices are located at 110 N. Marienfeld Street, Midland, TX 79701 and its telephone number is (432) 687-1575.

For more information about Endeavor, please see the section entitled “Description of Endeavor’s Business” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations of Endeavor.”

Endeavor Manager, LLC, a Texas limited liability company, is the managing member of Endeavor Parent, LLC. Its principal executive offices are located at 110 N. Marienfeld Street, Midland, TX 79701 and its telephone number is (432) 687-1575.

We are furnishing this proxy statement as part of the solicitation of proxies by the Board for use at the special meeting and at any properly convened meeting following an adjournment or postponement of the special meeting.

The special meeting will be held in person on [  ], 2024, at [  ] Central Time at Petroleum Club of Midland, 501 West Wall Street, Midland, TX 79701. If you plan to attend the special meeting in person, please arrive at least 15 minutes before the start time of the special meeting.

You will need proof of ownership of our common stock to attend the special meeting in person. If your shares of Diamondback common stock are in the name of your broker or bank or other nominee, you will need to bring evidence of your stock ownership, such as your most recent brokerage statement. All Diamondback stockholders will be required to present valid picture identification. IF YOU DO NOT HAVE VALID PICTURE IDENTIFICATION AND PROOF THAT YOU OWN SHARES OF DIAMONDBACK COMMON STOCK AS OF THE RECORD DATE, YOU MAY NOT BE ADMITTED INTO THE SPECIAL MEETING.

At the special meeting, stockholders of record will be asked to consider and vote on the following proposals:

The Board carefully reviewed and considered the terms and conditions of the Merger Agreement, and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment. By a unanimous vote, the Board: (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment are fair to and in the best interests of Diamondback and the holders of Diamondback common stock; (ii) approved and declared advisable the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; (iii) resolved to recommend that the holders of Diamondback common stock approve the Stock Issuance Proposal and the Charter Amendment Proposal; (iv) approved the execution, delivery and performance by Diamondback of the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; and (v) authorized and approved the submission of the Stock Issuance Proposal and the Charter Amendment Proposal for approval by the holders of Diamondback common stock.

The Board unanimously recommends that you vote “FOR” the Stock Issuance Proposal, “FOR” the Charter Amendment Proposal and “FOR” the Adjournment Proposal.

Each holder of record of shares of common stock as of the close of business on the record date is entitled to receive notice of, and to vote at, the special meeting. You will be entitled to one vote for each share of common stock that you owned on the record date. As of [  ], 2024, there were [  ] shares of common stock issued and outstanding and entitled to vote at the special meeting. The presence at the special meeting, by attendance in person or by proxy, of the holders of shares of the outstanding common stock representing a majority of the voting power of all outstanding shares of common stock to vote at the special meeting constitutes a quorum for the special meeting.

If you are a stockholder of record of and you vote by mail, by telephone or through the internet or at the special meeting via the virtual meeting website, then your shares of common stock will be counted as part of the quorum. If you are a “street name” holder of shares of common stock and you provide your bank, broker, trust or other nominee with voting instructions, then your shares will be counted in determining the presence of a quorum. If you are a “street name” holder of shares of common stock and you do not provide your bank, broker, trust or other nominee with voting instructions, then your shares will not be counted in determining the presence of a quorum.

All shares of common stock held by stockholders of record that are present at the special meeting in person or represented by proxy and entitled to vote at the special meeting, regardless of how such shares are voted or whether such stockholders abstain from voting, will be counted in determining the presence of a quorum. In the absence of a quorum, the special meeting may be adjourned.

The Stock Issuance Proposal requires, assuming a quorum is present, the affirmative vote of a majority of shares of the votes cast at the special meeting, whether in person or represented by proxy (meaning that of the votes cast at the special meeting, a majority of them must be voted “for” the proposal for it to be approved). Abstentions will have no effect on the Stock Issuance Proposal. Assuming a quorum is present, a failure to vote or otherwise be present at the special meeting will have no effect on the Stock Issuance Proposal.

The Charter Amendment Proposal requires the affirmative vote of the holders of a majority of the outstanding shares of common stock (meaning that of the outstanding shares of common stock, a majority of them must be voted “for” the proposal for it to be approved). Abstentions and failure to vote will have the same effect as a vote “AGAINST” the Charter Amendment Proposal.

The Adjournment Proposal requires, assuming a quorum is present, the affirmative vote of a majority of the votes cast at the special meeting, whether in person or represented by proxy (meaning that of the votes cast at the special meeting, a majority of them must be voted “for” the proposal for it to be approved). Abstentions will have no effect on the Adjournment Proposal. Assuming a quorum is present, a failure to vote or otherwise be present at the special meeting will have no effect on the Adjournment Proposal.

The Stock Issuance Proposal requires, assuming a quorum is present, the affirmative vote of a majority of the votes cast at the special meeting, whether in person or represented by proxy. Therefore, abstentions will no effect on this proposal.

The Charter Amendment Proposal requires the affirmative vote of the holders of a majority of the outstanding shares of common stock. Therefore, abstentions will have the same effect as a vote “AGAINST” the proposal.

The Adjournment Proposal requires, assuming a quorum is present, the affirmative vote of a majority of the votes cast at the special meeting, whether in person or represented by proxy. Therefore, abstentions from voting will no effect on this proposal.

A broker non-vote with respect to common stock occurs when (i) shares of common stock held by a broker or other nominee are represented, in person or by proxy, at a meeting of Diamondback stockholders, (ii) the bank, broker or other nominee has not received voting instructions from the beneficial owner on a particular proposal and (iii) the bank, broker or other nominee does not have the discretion to direct the voting of the shares of common stock on a particular proposal but has discretionary voting power on other proposals. A bank, broker, trust or other nominee may exercise discretion in voting on routine matters but may not exercise discretion and therefore will not vote on non-routine matters if instructions are not given.

Under applicable stock exchange rules, all of the proposals in this proxy statement are non-routine matters. As a result, there will not be any broker non-votes at the special meeting.

Accordingly, if your shares of common stock are held in “street name,” a bank, broker, trust or other nominee will NOT be able to vote your shares, and your shares will not be counted in determining the presence of a quorum unless you have properly instructed your bank, broker, trust or other nominee on how to vote. Because the approval of the Charter Amendment Proposal requires the affirmative vote of a majority of the

outstanding shares of common stock, the failure to provide your bank, broker, trust or other nominee with voting instructions will have the same effect as a vote “AGAINST” the Charter Amendment Proposal. Because the approval of each of (i) the Stock Issuance Proposal and (ii) the Adjournment Proposal requires the affirmative vote of a majority of the votes cast at the special meeting, whether in person or represented by proxy and because your bank, broker, trust or other nominee does not have discretionary authority to vote on such proposal, the failure to provide your bank, broker, trust or other nominee with voting instructions will have no effect on approval of those proposals.

At the close of business on March 11, 2024, directors and executive officers of Diamondback were entitled to vote 879,703 shares of common stock, representing less than 1% of the shares of common stock issued and outstanding on that date. Directors and executive officers of Diamondback have informed Diamondback that they intend to vote their shares in favor of the Stock Issuance Proposal, the Charter Amendment Proposal and Adjournment Proposal, although none of the directors and executive officers are obligated to do so.

Stockholders have a choice of voting by proxy by completing a proxy card and mailing it in the prepaid envelope provided, by calling a toll-free telephone number or through the internet. Please refer to your proxy card or the information forwarded by your bank, broker, trust or other nominee to see which options are available to you. The telephone and internet voting facilities for stockholders of record will close at 11:59 p.m. Eastern Time (i.e. 10:59 p.m. Central Time) on the day immediately preceding the date of the special meeting.

If you submit your proxy by mail, by telephone or through the internet voting procedures, but do not include “FOR,” “AGAINST” or “ABSTAIN” on a proposal to be voted, your shares will be voted in favor of that proposal. If you indicate “ABSTAIN” on a proposal to be voted, it will have the same effect as a vote “AGAINST” the Charter Amendment Proposal but no effect on the Stock Issuance Proposal or the Adjournment Proposal.

If you wish to vote by proxy and your shares are held by a bank, broker, trust or other nominee, you must follow the voting instructions provided to you by your bank, broker, trust or other nominee. Unless you give your bank, broker, trust or other nominee instructions on how to vote your shares of common stock, your bank, broker, trust or other nominee will not be able to vote your shares on the proposals.

If you wish to vote by attending the special meeting in person and your shares are held in the name of a bank, broker or other holder of record, you must obtain a legal proxy, executed in your favor, from the bank, broker or other holder of record authorizing you to vote at the special meeting. Obtaining a legal proxy may take several days.

If you do not submit a proxy or otherwise vote your shares of common stock in any of the ways described above, it will have the same effect as a vote “AGAINST” the Charter Amendment Proposal, but, assuming a quorum is present, will have no effect on the approval of the Stock Issuance Proposal or the Adjournment Proposal.

Any proxy given by a stockholder of may be revoked at any time before it is voted at the special meeting by doing any of the following:

“Street name” holders of shares of common stock should contact their bank, broker, trust or other nominee to obtain instructions as to how to revoke or change their proxies.

Although it is not currently expected, the special meeting may be adjourned or postponed one or more times to a later day or time if necessary or appropriate, including to solicit additional proxies if there are not sufficient votes cast at the special meeting to approve the Stock Issuance Proposal. Your shares of common stock will be voted on any adjournment proposal in accordance with the instructions indicated in your proxy or, if no instructions were provided, “FOR” the proposal.

If a quorum is present at the special meeting, the special meeting may be adjourned by the affirmative vote of a majority of the shares of common stock present at the special meeting, whether in person or represented by proxy, entitled to vote on such matter. The adjourned meeting may take place without further notice other than by an announcement made at the special meeting unless the adjournment is for more than 30 days thereafter or, if, after the adjournment, a new record date is fixed for the adjourned meeting, in which case a notice of the adjourned meeting will be given to each stockholder of record entitled to vote at the special meeting. Additionally, our bylaws provide that the special meeting may be adjourned by the chairman of the special meeting, from time to time, whether or not there is a quorum, to reconvene at the same or some other place.

At this time we have not engaged a proxy solicitor. If we do engage a proxy solicitor we will pay the customary costs associated with such engagement. We will reimburse brokerage firms and others for their reasonable expenses in forwarding solicitation materials to beneficial owners of our common stock. Diamondback is paying the cost of printing and mailing proxy materials. In addition to the solicitation of proxies by mail, solicitation may be made by our directors, officers and other associates by personal interview, telephone, facsimile or electronic mail. No additional compensation will be paid to these persons for solicitation.

Broadridge Financial Solutions, Inc. will tabulate the votes cast at the special meeting.

Representatives of Grant Thornton LLP, our independent auditor, are expected to be present at the special meeting, will have the opportunity to make a statement (if they desire to do so) and are expected to be available to respond to appropriate questions raised at the special meeting.

For additional questions about the special meeting, assistance in submitting proxies or voting shares of common stock, or additional copies of this proxy statement or the enclosed proxy card, please write to Corporate Secretary, Diamondback Energy, Inc., 500 West Texas Ave, Suite 100, Midland, TX 79701.

Diamondback is asking its stockholders to approve, for the purposes of complying with the applicable provisions of Nasdaq Listing Rule 5635, the issuance of an aggregate of 117,267,069 shares of common stock in connection with the Merger.

The Board unanimously recommends that the stockholders vote “FOR” the Stock Issuance Proposal.

If you return a properly executed proxy card, but do not indicate instructions on your proxy card, then your shares of common stock represented by such proxy card will be voted “FOR” the Stock Issuance Proposal.

The approval of this proposal requires, assuming a quorum is present, the affirmative vote of a majority of the votes cast at the special meeting, whether in person or represented by proxy (meaning that of the votes cast at the special meeting, a majority of them must be voted “for” the proposal for it to be approved). Abstentions will have no effect on the Stock Issuance Proposal. Assuming a quorum is present, a failure to vote or otherwise be present at the special meeting will have no effect on the Stock Issuance Proposal.

As discussed elsewhere in this proxy statement, Diamondback stockholders will consider and vote on a proposal to adopt an amendment to the Charter to increase the total number of authorized shares of common stock under the Charter from 400 million shares to 800 million shares of common stock.

If Diamondback stockholders approve the Charter Amendment Proposal, then Diamondback expects to file a Certificate of Amendment with the Secretary of State of the State of Delaware to increase the number of authorized shares under the terms of its Charter of its capital stock from 410,000,000 shares to 810,000,000 shares and common stock from 400,000,000 shares to 800,000,000 shares. Upon filing of the Certificate of Amendment with the Secretary of State of the State of Delaware, Section 4.1 of the Charter will be amended and restated in its entirety to read as follows:

Authorized Capital Stock. The total number of shares of capital stock that the Corporation is authorized to issue is 810,000,000 shares, divided into two classes consisting of 800,000,000 shares of common stock, par value $0.01 per share (“Common Stock”), and 10,000,000 shares of preferred stock, par value $0.01 per share (“Preferred Stock”).

The Board unanimously recommends that stockholders vote “FOR” the Charter Amendment Proposal.

If you return a properly executed proxy card, but do not indicate instructions on your proxy card, then your shares of common stock represented by such proxy card will be voted “FOR” this proposal.

The approval of this proposal requires the affirmative vote of the holders of a majority of the outstanding shares of common stock (meaning that of the outstanding shares of common stock, a majority of them must be voted “for” the proposal for it to be approved). Abstentions and failure to vote will have the same effect as a vote “AGAINST” the Charter Amendment Proposal.

Diamondback’s stockholders may be asked to adjourn the special meeting to a later date or time if necessary or appropriate, including to solicit additional proxies if there are not sufficient votes cast at the special meeting to approve the Stock Issuance Proposal.

The Board unanimously recommends that stockholders vote “FOR” the Adjournment Proposal.

If you return a properly executed proxy card, but do not indicate instructions on your proxy card, then your shares of common stock represented by such proxy card will be voted “FOR” this proposal.

The approval of this proposal requires, assuming a quorum is present, the affirmative vote of a majority of the votes cast at the special meeting, whether in person or represented by proxy (meaning that of the votes cast at the special meeting, a majority of them must be voted “for” the proposal for it to be approved). Abstentions will have no effect on the Adjournment Proposal. Assuming a quorum is present, a failure to vote or otherwise be present at the special meeting will have no effect on the Adjournment Proposal.

If a quorum is present at the special meeting, the special meeting may be adjourned by the affirmative vote of a majority of the shares of common stock present at the special meeting, whether in person or represented by proxy, entitled to vote on such matter. The adjourned meeting may take place without further notice other than by an announcement made at the special meeting unless the adjournment is for more than 30 days thereafter or, if, after the adjournment, a new record date is fixed for the adjourned meeting, in which case a notice of the adjourned meeting will be given to each stockholder of record entitled to vote at the special meeting. Additionally, our bylaws provide that the special meeting may be adjourned by the chairman of the special meeting, from time to time, whether or not there is a quorum, to reconvene at the same or some other place.

Diamondback entered into the Merger Agreement with Endeavor on February 11, 2024, which was amended on March 18, 2024. Under the terms of the Merger Agreement, subject to the satisfaction or waiver of specified closing conditions, Merger Sub I will merge with and into Endeavor, with Endeavor surviving the First Merger as the First Surviving Company. Immediately following the First Merger, the First Surviving Company will merge with and into Merger Sub II, with Merger Sub II surviving as a wholly owned subsidiary of Diamondback. The Board has determined that the Merger Agreement is fair to, and in the best interest of, Diamondback and its stockholders and has approved and declared advisable the Merger Agreement and the transactions contemplated thereby, including the Merger and the Stock Issuance.

If the Merger is completed, the aggregate consideration in exchange for the Endeavor Interests will be (i) cash consideration of $8.0 billion, subject to adjustments in accordance with the terms of the Merger Agreement, and (ii) 117,267,069 shares of common stock. The common stock to be issued in connection with the Merger will not be registered under the Securities Act and will be issued in reliance on the exemption from registration requirements thereof provided by Section 4(a)(2) of the Securities Act as a transaction by an issuer not involving a public offering.

The Board and Diamondback’s senior management regularly evaluate and pursue potential investments, purchases and sales of assets and businesses, joint ventures, strategic business combinations and other transactions with the potential to advance Diamondback’s strategic objectives and enhance stockholder value. In furtherance of these efforts, senior executives of Diamondback, including Mr. Travis D. Stice, Chairman of the Board and Chief Executive Officer of Diamondback, Mr. Kaes Van’t Hof, President and Chief Financial Officer of Diamondback, Mr. Jere W. Thompson III, Diamondback’s Executive Vice President of Strategy and Corporate Development and Mr. Matt Zmigrosky, Diamondback’s Executive Vice President, Chief Legal and Administrative Officer and Secretary, have from time to time engaged in discussions about potential strategic transaction opportunities with representatives of other companies and updated the Board regarding these interactions during regularly scheduled and special meetings.

In November 2023, as part of their ongoing evaluation of strategic transactions to enhance stockholder value, Diamondback’s senior management, with assistance from Jefferies LLC (“Jefferies”), Diamondback’s lead financial advisor, assessed the potential merits and risks of a business combination transaction between Diamondback and Endeavor based on publicly available information.

On December 8, 2023, Mr. Stice called Mr. Lance Robertson, the Chief Executive Officer and President of Endeavor, and expressed Diamondback’s interest in a potential business combination transaction between Diamondback and Endeavor. Later on December 8, 2023, following the conversation, Mr. Stice delivered a letter addressed to Mr. Autry Stephens, Endeavor’s founder and controlling equityholder, and Mr. Robertson, in which Diamondback requested the opportunity to work with Endeavor to explore a potential business combination transaction between the two companies and ascribed a value of at least $25 billion to Endeavor, based on preliminary analysis using publicly available information.

On December 18, 2023, Messrs. Stice and Robertson had a call to discuss potential next steps in exploring the proposed transaction, including due diligence information that Diamondback would need to refine its views on the valuation of Endeavor. Later on December 18, 2023, following the call, Mr. Stice sent Mr. Robertson a draft mutual confidentiality agreement, to facilitate discussions and the disclosure of information between Diamondback and Endeavor, and a due diligence request list.

Mr. Zmigrosky and Mr. Will Krueger, the General Counsel of Endeavor, subsequently negotiated, and on December 21, 2023, the parties executed, the mutual confidentiality agreement, which contained no “standstill” or similar provisions applicable to either party.

Later on December 21, 2023, Endeavor provided Diamondback with access to a virtual data room containing certain preliminary due diligence information. The Endeavor virtual data room was iteratively updated with additional due diligence information responsive to requests for additional information and documents throughout the ensuing transaction negotiations.

Between December 21, 2023 and February 11, 2024, representatives of Diamondback conducted due diligence on Endeavor, including participating in a number of management meetings and due diligence discussions with representatives of Endeavor.

On December 22, 2023, Messrs. Stice and Van’t Hof had a call with Mr. Robertson in which they discussed certain matters relating to the proposed transaction, including the potential governance structure of the combined company and certain employee matters. Mr. Robertson advised Messrs. Stice and Van’t Hof that Endeavor would provide additional due diligence materials to enable Diamondback to refine its valuation analysis of Endeavor. Messrs. Stice and Van’t Hof indicated to Mr. Robertson that Diamondback could be in a position to provide a non-binding proposal letter for a transaction with Endeavor following a meeting of the Board scheduled to occur in mid-January 2024.

On January 12, 2024, the Board met, with members of Diamondback’s management and representatives of Jefferies and Citigroup Global Markets Inc. (“Citi”), Diamondback’s M&A and Capital Markets advisor, in attendance. At the meeting, members of Diamondback’s management provided the Board with an overview of the status of discussions with Endeavor, their due diligence to date and their current assessment of the potential benefits and risks of a potential transaction with Endeavor. Following discussion among the Board, Diamondback’s management and the representatives of Jefferies and Citi, the Board authorized management to deliver a non-binding proposal for a business combination transaction reflecting an enterprise value of $26 billion for Endeavor.

Later that day, Mr. Stice called Mr. Robertson to preview the terms of the non-binding proposal letter (the “January 12 Letter”) that Diamondback would send to Endeavor, and shortly thereafter, delivered the January 12 Letter to Mr. Robertson. The January 12 Letter proposed a business combination transaction between Endeavor and Diamondback for consideration to Endeavor’s equityholders consisting of $10 billion in cash and $16 billion in Diamondback common stock, certain governance rights for Endeavor’s equityholders in the combined company, including the right to nominate two directors for election to the Board, and certain rights, restrictions and obligations for Endeavor’s equityholders as stockholders of the combined company.

On January 16, 2024, Messrs. Stice and Thompson had a call with Mr. Robertson to further discuss the January 12 Letter and certain matters relating to the proposed transaction, including, among other things, the consideration mix between cash and Diamondback common stock, the structure of the proposed transaction and Diamondback’s contemplated financing of the proposed transaction.

On January 19, 2024, Messrs. Stice and Van’t Hof had a follow-up call with Mr. Robertson in which they discussed, among other things, post-closing governance arrangements and the potential for Diamondback to increase the equity portion of the transaction consideration.

On January 25, 2024, Messrs. Stice and Van’t Hof called Mr. Robertson to continue the ongoing discussion regarding the proposed transaction, including with respect to the consideration mix between Diamondback common stock and cash and mutual due diligence matters.

On January 27, 2024, Diamondback provided Endeavor with access to a virtual data room containing certain due diligence information concerning Diamondback. The virtual data room was iteratively updated with additional due diligence information responsive to requests for additional information and documents throughout the ensuing transaction negotiations. Between January 27, 2024 and February 11, 2024, representatives of Endeavor conducted due diligence on Diamondback, including participating in a number of management meetings and due diligence discussions with representatives of Diamondback.

On January 30, 2024, Mr. Robertson sent Mr. Stice a draft of the Merger Agreement and a term sheet setting forth Endeavor’s responses to Diamondback’s governance proposals set forth in the January 12 Letter (the “governance term sheet”). The draft Merger Agreement, among other things, provided Endeavor equityholders with the ability to elect to receive non-voting preferred stock of Diamondback in lieu of Diamondback common stock in excess of 19.99% of the outstanding Diamondback common stock (the “preferred stock election”), did not impose any restrictions on the ability of Endeavor to make distributions to its equityholders, proposed a termination fee of 3.5% of Endeavor’s transaction equity value that would be payable by Diamondback if the

Merger Agreement were to be terminated in certain circumstances, and imposed reciprocal interim operating restrictions on Diamondback and Endeavor. Endeavor also proposed in the governance term sheet that its former equityholders would have the right, subject to the satisfaction of certain ownership thresholds, to nominate up to four directors for the board of the combined company.

On January 31, 2024, during a regularly scheduled meeting of the Board, members of Diamondback’s management discussed with the Board the ongoing negotiations with Endeavor, including the merits and risks of the proposed transaction with Endeavor and the potential post-closing governance structure of the combined company. Following the Board meeting on January 31, 2024, Mr. Van’t Hof sent a revised version of the governance term sheet back to Mr. Robertson indicating, among other things, that Diamondback was willing to accept Endeavor’s proposed number of director nominees, subject to agreement on other terms with respect to the rights and obligations of the Endeavor equityholders as stockholders of the combined company.

Later on January 31, 2024, Messrs. Stice and Van’t Hof had a call with Mr. Robertson and discussed the governance term sheet and certain terms in the draft Merger Agreement, including the preferred stock election provision and the ability of Endeavor to make distributions to its equityholders in the period between the signing and closing of the proposed transaction. Later that day, Mr. Stice sent a draft of the Stockholders Agreement to Mr. Robertson.

On February 1, 2024, Messrs. Stice and Van’t Hof had a call with Mr.  Robertson and discussed certain terms of the proposed transaction, including the consideration mix between Diamondback common stock and cash.

Also on February 1, 2024, representatives of Wachtell, Lipton, Rosen & Katz (“Wachtell Lipton”), counsel to Diamondback, sent a revised draft of the Merger Agreement to representatives of Paul, Weiss, Rifkind, Wharton & Garrison (“Paul Weiss”), counsel to Endeavor. The revised draft, among other things, removed the preferred stock election provision and certain interim operating covenant restrictions on Diamondback, imposed certain limitations on the amount Endeavor was permitted to distribute to its equityholders during the interim period and added certain exceptions to the non-solicitation obligations of Diamondback with respect to alternative transactions.

On February 3, 2024, Mr. Stice called Mr. Robertson to discuss the status of Endeavor’s review of the proposed transaction terms. Later on February 3, 2024, following the conversation, Mr. Stice sent an email to Mr. Robertson, in which, among other things, he emphasized that Diamondback needed confirmation that Diamondback’s proposals regarding the consideration mix and the framework for permitted distributions by Endeavor during the interim period were acceptable to Endeavor.

On February 4, 2024, Mr. Stice had a conversation with Mr. Chuck Meloy, the former Chief Executive Officer of Endeavor, about the proposed transaction, ahead of Mr. Meloy’s meetings with Mr. Stephens and senior management of Endeavor with respect to the proposed transaction.

On February 6, 2024, representatives of Paul Weiss delivered a revised draft of the Merger Agreement and Stockholders Agreement to representatives of Wachtell Lipton. The revised draft of the Merger Agreement, among other things, contained a modified preferred stock election provision, increased the ability of Endeavor to make distributions and certain other payments in the interim period, and imposed additional restrictions on Diamondback regarding soliciting alternative transactions.

On February 7, 2024, Messrs. Stice and Van’t Hof called Messrs. Meloy and Robertson to discuss the key remaining open points in the Merger Agreement, including the preferred stock election provision and scope of non-solicitation restrictions on Diamondback, and certain other matters relating to the proposed transaction. Also on February 7, 2024, at a virtual meeting, members of Endeavor’s management answered due diligence questions from members of Diamondback’s management and representatives of Wachtell Lipton.

On February 8, 2024, at a virtual meeting, members of Diamondback’s management answered due diligence questions from members of Endeavor’s management and representatives of Paul Weiss and J.P. Morgan Securities LLC, Endeavor’s M&A advisor.

Also on February 8, 2024, representatives of Wachtell Lipton sent revised drafts of the Merger Agreement and Stockholders Agreement to representatives of Paul Weiss. The revised Merger Agreement, among other

things, removed the modified preferred stock election provision, reduced the amount Endeavor was permitted to distribute to its equityholders during the interim period and generally accepted the more restrictive non-solicitation provisions on Diamondback requested by Endeavor.

Following additional discussions among principals and their respective outside counsels on February 8 and 9, 2024, the parties reached agreement that there would not be any preferred stock election provision in the Merger Agreement and that Diamondback’s management would recommend to the Board a transaction in which Endeavor would be valued at $26 billion, with $8 billion of the consideration payable in cash (subject to agreed adjustments) and $18 billion payable in Diamondback common stock.

On February 9, 2024, after the close of market, Messrs. Stice and Van’t Hof discussed with Mr. Robertson the measurement price for valuing Diamondback common stock to be issued in the transaction and, after negotiation, agreed that the Diamondback common stock would be valued at its 30-day volume weighted average price as of February 9, 2024. Messrs. Stice, Van’t Hof and Robertson also discussed next steps and actions, with a view towards announcing the transaction on February 12, 2024, assuming the Board and Endeavor equityholders approved the transaction.

Representatives of Wachtell Lipton and Diamondback’s management continued to negotiate the terms of the Merger Agreement with representatives of Paul Weiss and Endeavor’s management from February 9 through February 11, 2024. The parties reached agreement during these negotiations on other transaction terms, including the scope of non-solicitation restrictions on Diamondback, the termination fee payable by Diamondback under certain circumstances and the parties’ respective interim operating covenants.

The Merger Agreement and Stockholders Agreement were in substantially final form by the morning of February 11, 2024, when the Board met to consider approval of the proposed transaction, with representatives of Wachtell Lipton and Jefferies in attendance. Representatives of Wachtell Lipton discussed the Board’s fiduciary duties in the context of the proposed transaction and reviewed with the Board the terms of the Merger Agreement and the Stockholders Agreement. Representatives of Jefferies reviewed, with the Board, Jefferies’s analysis of the financial terms of the proposed transaction. Following discussion, Jefferies rendered its oral opinion to the Board, which was subsequently confirmed by delivery of a written opinion, that, as of February 11, 2024 and based upon and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations set forth therein, the merger consideration to be paid by Diamondback pursuant to the Merger Agreement was fair, from a financial point of view, to Diamondback. See the section entitled “—Opinion of Diamondback’s Financial Advisor” for more information.

After considering the terms of the proposed transaction with Endeavor, and taking into consideration the matters discussed during that meeting and prior meetings of the Board, including the factors described under the section entitled “—Reasons for the Merger; Recommendations of the Board of Directors”, the Board unanimously (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment, are fair to and in the best interests of Diamondback and the holders of Diamondback common stock; (ii) approved and declared advisable the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; (iii) resolved to recommend that the holders of Diamondback common stock approve the Stock Issuance Proposal and the Charter Amendment Proposal; (iv) approved the execution, delivery and performance by Diamondback of the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; and (v) authorized and approved the submission of the Stock Issuance Proposal and the Charter Amendment Proposal for approval by the holders of Diamondback common stock.

On February 11, 2024, following the Board meeting, Diamondback and Endeavor executed the Merger Agreement.

Prior to the opening of trading on February 12, 2024, Diamondback and Endeavor issued a joint press release announcing entry into the Merger Agreement.

On March 18, 2024, Diamondback and Endeavor executed a Letter Agreement, amending the Merger Agreement, to amend and restate the form of Stockholders Agreement.

The Board carefully reviewed and considered the terms and conditions of the Merger Agreement, and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment. By a unanimous

vote, the Board: (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment are fair to and in the best interests of Diamondback and the holders of Diamondback common stock; (ii) approved and declared advisable the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; (iii) resolved to recommend that the holders of Diamondback common stock approve the Stock Issuance Proposal and the Charter Amendment Proposal; (iv) approved the execution, delivery and performance by Diamondback of the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and the Charter Amendment; and (v) authorized and approved the submission of the Stock Issuance Proposal and the Charter Amendment Proposal for approval by the holders of Diamondback common stock. The Board unanimously recommends that Diamondback stockholders vote “FOR” the Stock Issuance Proposal and “FOR” the Charter Amendment Proposal.

In arriving at its decision to approve the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, and to recommend that Diamondback stockholders vote their shares of common stock in favor of the approval of the Stock Issuance Proposal, the Board consulted with Diamondback’s management team, outside legal counsel and Diamondback’s financial advisors, and considered a number of factors, including the following factors (not necessarily in order of relative importance) that the Board viewed as being generally positive or favorable in coming to its determination, approval and related recommendation:

The Board also considered and balanced against the potentially positive factors a number of uncertainties, risks, and factors it deemed generally negative or unfavorable in making its determination, approval, and related recommendation, including the following (not necessarily in order of relative importance):

The Board considered all of these factors as a whole, as well as others, and, on balance, concluded that the potential benefits of the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, to Diamondback and Diamondback stockholders outweighed the associated risks, uncertainties, restrictions, and potentially negative factors. As a result, the Board recommends that that Diamondback stockholders approve the Stock Issuance Proposal.

The foregoing discussion of factors considered by the Board is not intended to be exhaustive but is meant to include material factors considered by the Board. The Board collectively reached the conclusion to approve the Stock Issuance and submit the Stock Issuance Proposal to Diamondback stockholders in light of the various factors described above and other factors that the members of the Board believed were appropriate. Given the variety of factors considered in connection with its evaluation of the Merger Agreement and the transactions contemplated thereby, including the Stock Issuance, the Board did not find it practicable to, and did not, quantify or otherwise assign relative weights to the specific factors considered in reaching its determinations and recommendations. Moreover, each member of the Board applied his or her own personal business judgment to the process and may have given different weight to different factors. The Board did not undertake to make any specific determination as to whether any factor, or any particular aspect of any factor, supported or did not support its ultimate determination. The Board based its recommendation on the totality of the information available to it, including discussions with Diamondback’s management team and outside legal and financial advisors.

It should be noted that this explanation of the reasoning of the Board and certain information presented in this section is forward-looking in nature and should be read in light of the factors set forth in the section entitled “Cautionary Statement Regarding Forward-Looking Statements.”

Diamondback does not as a matter of course make public long-term forecasts or internal projections as to future performance, revenues, earnings or other results due to, among other reasons, the uncertainty of the underlying assumptions and estimates. However, in connection with its evaluation of the Merger Agreement and the transactions contemplated thereby, including the Merger and Stock Issuance, Diamondback’s management prepared certain non-public unaudited internal financial forecasts with respect to Diamondback and Endeavor, which were provided to the Board in connection with its evaluation of the contemplated Merger and Stock Issuance (collectively, the “Diamondback forecasted financial information”). The Diamondback forecasted financial information was also provided to Jefferies for its use and reliance, as directed by Diamondback, in connection with the financial analyses that Jefferies performed in connection with its opinion described in ‘‘—Opinion of Diamondback’s Financial Advisor.” The inclusion of this information should not be regarded as an indication that any of Diamondback, Endeavor, their respective advisors, or other representatives or any other recipient of this information considered, or now considers, it to be necessarily predictive of actual future performance or events, or that it should be construed as financial guidance, and such summary projections set forth below should not be relied on as such.

This information was prepared solely for internal use and is subjective in many respects. While presented with numeric specificity, the Diamondback forecasted financial information reflects numerous estimates and assumptions that are inherently uncertain and may be beyond the control of Diamondback’s management, including, among others, Diamondback’s and Endeavor’s future results, difficulties in appropriately allocating capital and resources among strategic opportunities, the timing and extent of success in discovering, developing, producing and estimating reserves, market conditions and prices for oil, natural gas and NGLs, including regional basis differentials, capital availability, general economic and regulatory conditions, and other matters described in “Cautionary Statement Regarding Forward-Looking Statements” and “Risk Factors.” The Diamondback forecasted financial information reflects both assumptions as to certain business decisions that are subject to change and, in many respects, subjective judgment, and thus is susceptible to multiple interpretations and periodic revisions based on actual experience and business developments. Diamondback and Endeavor can give no assurance that the Diamondback forecasted financial information and the underlying estimates and assumptions will be realized. In addition, since the Diamondback forecasted financial information is inherently forward looking and covers multiple years, such information by its nature becomes less predictive with each successive year. Actual results may differ materially from those set forth below, and important factors that may affect actual results and cause the Diamondback forecasted financial information to be inaccurate include, but are not limited to, risks and uncertainties relating to Diamondback’s and Endeavor’s respective businesses, industry performance, the regulatory environment, general business and economic conditions, and other matters described in “Risk Factors.” Please also see “Cautionary Statement Regarding Forward-Looking Statements” and “Where You Can Find More Information.”

The Diamondback forecasted financial information was not prepared with a view toward compliance with GAAP, published guidelines of the SEC or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information. The Diamondback forecasted financial information included in this proxy statement has been prepared by, and is the responsibility of, the management of Diamondback. Neither Grant Thornton LLP, Diamondback’s independent registered public accounting firm, nor any other independent accountant, has audited, reviewed, examined, compiled nor applied agreed-upon procedures with respect to the accompanying unaudited prospective financial information and, accordingly, they do not express an opinion or any other form of assurance with respect thereto.

Furthermore, the Diamondback forecasted financial information does not take into account any circumstances or events occurring after the date it was prepared. Diamondback can give no assurance that, had the Diamondback forecasted financial information been prepared either as of the date of this proxy statement or as of the date of the special meeting, similar estimates and assumptions would be used. Except as required by applicable securities laws, Diamondback does not intend to, and disclaims any obligation to, make publicly available any update or other revision to the Diamondback forecasted financial information to reflect circumstances existing since their preparation or to reflect the occurrence of unanticipated events, even in the

event that any or all of the underlying assumptions are shown to be in error, including with respect to the accounting treatment of the Merger and Stock Issuance under GAAP, or to reflect changes in general economic or industry conditions.

The Diamondback forecasted financial information does not take into account all the possible financial and other effects on Diamondback or Endeavor of the Merger and Stock Issuance, the effect on Diamondback or Endeavor of any business or strategic decision or action that has been or will be taken as a result of the Merger Agreement having been executed, the effect of any business or strategic decisions or actions which would likely have been taken if the Merger Agreement had not been executed, but which were instead altered, accelerated, postponed, or not taken in anticipation of the Merger and Stock Issuance. Further, the Diamondback forecasted financial information does not take into account the effect on Diamondback or Endeavor of any possible failure of the Merger to occur. None of Diamondback or its affiliates, officers, directors, advisors, or other representatives has made, makes, or is authorized in the future to make any representation to any Diamondback stockholder or other person regarding Diamondback’s or Endeavor’s ultimate performance compared to the information contained in the Diamondback forecasted financial information or that the forecasted results will be achieved. The inclusion of the Diamondback forecasted financial information herein should not be deemed an admission or representation by Diamondback or its advisors or other representatives or any other person that the forecasts will be achieved, particularly in light of the inherent risks and uncertainties associated with such forecasts. The summary of the Diamondback forecasted financial information included below is not being included to influence Diamondback stockholders’ decision whether to vote in favor of the proposals to be considered at the special meeting, but is being provided solely because it was made available to the Board and Diamondback’s financial advisors in connection with the Merger and the Stock Issuance.

In light of the foregoing, and considering that the special meeting will be held several months after the Diamondback forecasted financial information was prepared, as well as the uncertainties inherent in any forecasted information, Diamondback stockholders are cautioned not to place undue reliance on such information, and Diamondback urges the Diamondback stockholders to review Diamondback’s most recent SEC filings for a description of Diamondback’s reported financial results. Please see “Where You Can Find More Information.”

The following table sets forth certain summarized prospective financial information regarding Diamondback on a standalone basis for the years ending December 31, 2024 through 2028 (the “Diamondback projections for Diamondback”), which information was prepared by Diamondback’s management, provided to the Board and directed by Diamondback to be used and relied upon by Jefferies in connection with the financial analyses that it performed in connection with its opinion described in “ —Opinion of Diamondback’s Financial Advisor.” The Diamondback projections for Diamondback should not be regarded as an indication that Diamondback considered, or now considers, it to be necessarily predictive of actual future performance or events, or that such information should be construed as financial guidance, and such information does not take into account any circumstances or events occurring after the date it was prepared. In preparing the Diamondback projections for Diamondback, Diamondback's management team used, for the projection periods, two different scenarios regarding commodity prices. The summarized prospective financial information in the table immediately below reflect the first scenario, which assumes a flat price of $75.00/bbl with respect to oil and a flat price of $3.00/MMBtu with respect to natural gas

The summarized prospective financial information in the table immediately below reflects the second scenario, which assumes First Call WTI Pricing for oil prices reflecting Wall Street research consensus estimates (as of February 9, 2024) for 2024 and 2025 (which were $75.61/bbl and $71.27/bbl for oil in 2024 and 2025, respectively, and $3.09/MMBtu and $3.79/MMBtu for natural gas in 2024 and 2025, respectively), remaining constant at 2025 levels thereafter.

The following tables set forth certain summarized prospective financial information regarding Endeavor on a standalone basis for the years ending December 31, 2024 through 2028 (the “Diamondback projections for Endeavor”), which information was prepared by Diamondback’s management, provided to the Board and directed by Diamondback to be used and relied upon by Jefferies in connection with the financial analyses that Jefferies performed in connection with its opinion described in “ —Opinion of Diamondback’s Financial Advisor.” The Diamondback projections for Endeavor should not be regarded as an indication that Diamondback considered, or now considers, it to be necessarily predictive of actual future performance or events, or that such information should be construed as financial guidance, and such information does not take into account any circumstances or events occurring after the date it was prepared.

In preparing the Diamondback projections for Endeavor, Diamondback’s management team used, for the projection periods, two different scenarios regarding commodity prices. The summarized prospective financial information in the table immediately below reflects the first scenario, which assumes a flat price of $75.00/bbl with respect to oil and a flat price of $3.00/MMBtu with respect to natural gas.

The summarized prospective financial information in the table immediately below reflects the second scenario, which assumes First Call WTI Pricing for oil prices reflecting Wall Street research consensus estimates (as of February 9, 2024) for 2024 and 2025 (which were on average $75.61/bbl and $71.27/bbl for oil in 2024 and 2025, respectively, and $3.09/MMBtu and $3.79/MMBtu for natural gas in 2024 and 2025, respectively), remaining constant at 2025 levels thereafter.

Diamondback’s management estimated and provided to Jefferies for its use and reliance in connection with the financial analyses that Jefferies performed in connection with its opinion described in “ —Opinion of Diamondback’s Financial Advisor”, the following annual synergies in years 2025 and thereafter, which are included in the Diamondback projections for Endeavor (the “Diamondback expected synergies”):

The Diamondback expected synergies should not be regarded as an indication that Diamondback considered, or now considers, it to be necessarily predictive of actual future performance or events, or that such information should be construed as financial guidance, and such information does not take into account any circumstances or events occurring after the date it was prepared.

Pursuant to an engagement letter dated as of January 20, 2024, as amended on February 2, 2024, Diamondback retained Jefferies to act as its lead financial advisor in connection with a possible acquisition or series of related acquisitions by Diamondback of all or substantially all of the assets of Endeavor. At a meeting of the Board on February 11, 2024, Jefferies rendered an oral opinion, confirmed by delivery of a written opinion dated as of the same date, to the Board to the effect that, as of that date and based upon and subject to the various assumptions made, procedures followed, matters considered and limitations on the scope of the review undertaken by Jefferies as set forth in its opinion, the Merger Consideration to be paid by Diamondback pursuant to the Merger Agreement was fair, from a financial point of view, to Diamondback.

The full text of the written opinion of Jefferies, dated as of February 11, 2024, is attached hereto as Annex C. Jefferies’ opinion sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations on the scope of the review undertaken by Jefferies in rendering its opinion. Jefferies’ opinion was directed to the Board and addresses only the fairness, from a financial point of view, of the Merger Consideration to be paid by Diamondback pursuant to the Merger Agreement as of the date of the opinion to Diamondback. The summary of the opinion of Jefferies set forth below is qualified in its entirety by reference to the full text of the opinion, a copy of which is attached as Annex C to this proxy statement.

In arriving at its opinion, Jefferies, among other things:

In Jefferies’ review and analysis and in rendering its opinion, with the Board’s permission, Jefferies assumed and relied upon, but did not assume any responsibility to independently investigate or verify, the accuracy and completeness of all financial and other information that was supplied or otherwise made available by or on behalf of Diamondback or that was publicly available to Jefferies (including, without limitation, the information described above) or that was otherwise reviewed by Jefferies. Jefferies relied on assurances of Diamondback management that they were not aware of any facts or circumstances that would make such information inaccurate or misleading. In its review, Jefferies did not obtain any independent evaluation or appraisal of any of the assets or liabilities of, nor did Jefferies conduct a physical inspection of any of the properties or facilities of, Diamondback or Endeavor, nor was Jefferies furnished with any such evaluations or appraisals, nor did Jefferies assume any responsibility to obtain any such evaluations or appraisals.

With respect to the financial forecasts provided to Jefferies and, at the Board’s direction, reviewed by Jefferies, Jefferies’ opinion noted that projecting the future results of any company is inherently subject to uncertainty. With respect to the projections for each of Diamondback and Endeavor, in each case, prepared by Diamondback management and provided to Jefferies by Diamondback, the Board informed Jefferies, and Jefferies assumed with the Board's consent, that such financial forecasts were reasonably prepared on bases reflecting the best currently available estimates and good faith judgment of Diamondback management as to the future financial performance of Diamondback and Endeavor, as the case may be. Jefferies’ assumed with the Board’s consent, that the estimated tax benefits resulting from the Merger provided to Jefferies by Diamondback management were reasonably prepared by Diamondback management on bases reflecting the currently available estimates and judgments of Diamondback management as to the amount and timing of such estimated tax benefits. Diamondback management further advised Jefferies and, at the Board’s direction, Jefferies assumed, that the estimated tax benefits resulting from the Merger were reasonably achievable in the amounts and at the times projected. At the Board’s direction and with the Board’s consent, Jefferies assumed that the Diamondback expected synergies anticipated by Diamondback management to result from the Merger would be realized in the amounts and at the times projected. Jefferies expressed no opinion as to such financial forecasts or the assumptions on which they were made, including the Diamondback expected synergies and estimated tax benefits anticipated by Diamondback management to result from the Merger, nor did Jefferies express any opinion as to any potential pro forma effects of the transactions contemplated by the Merger Agreement, including the Merger.

Jefferies’ opinion was based on economic, monetary, regulatory, market and other conditions existing and which could be evaluated as of the date of its opinion. Jefferies expressly disclaimed any undertaking or obligation to advise any person of any change in any fact or matter affecting its opinion of which Jefferies becomes aware after the date of its opinion.

Jefferies made no independent investigation of, any legal or accounting or tax matters affecting Diamondback or Endeavor, and Jefferies assumed the correctness in all respects material to its analysis of all legal and accounting advice given to Diamondback and the Board, including, without limitation, advice as to the legal, accounting and tax consequences of the terms of, and transactions contemplated by, the Merger Agreement to Diamondback. Jefferies assumed that the final form of the Merger Agreement would be substantially similar to the last draft reviewed by Jefferies in all respects material to Jefferies’ opinion. Jefferies also assumed that the Merger would be consummated in accordance with the terms of the Merger Agreement without waiver, modification or amendment of any term, condition or agreement in any respect, material to the opinion. Jefferies assumed that in the course of obtaining the necessary regulatory or third-party approvals, consents and releases for the Merger, no delay, limitation, restriction or condition would be imposed that would have an adverse effect on Diamondback or Endeavor or the contemplated benefits of the Merger, in any respect material to Jefferies’ opinion. Jefferies expressed no opinion as to the price shares of Diamondback common stock or any other securities of Diamondback would trade at any future time.

Jefferies’ opinion was for the use and benefit of the Board (in its capacity as such) in its consideration of the transactions contemplated by the Merger Agreement, and its opinion did not address the relative merits of the transactions contemplated by the Merger Agreement as compared to any alternative transaction or opportunity that might be available to Diamondback, nor did it address the underlying business decision by Diamondback to engage in the transactions contemplated by the Merger Agreement, including the Merger. Jefferies’ opinion did not constitute a recommendation as to how any holder of Diamondback common stock should vote or act with respect to any matter related to the Merger, including, without limitation, with respect to approval of the issuance of Diamondback common stock in the Merger or approval of the proposed amendment to Diamondback's certificate of incorporation.

In addition, Jefferies was not asked to address, and its opinion did not address, the fairness to, or any other consideration of, the holders of any class of securities, creditors or other constituencies of Diamondback. Jefferies’ opinion was authorized by the fairness opinion committee of Jefferies.

In connection with rendering its opinion, Jefferies performed a variety of financial and comparative analyses. The preparation of a fairness opinion is a complex process involving various determinations as to the most appropriate and relevant quantitative and qualitative methods of financial analysis and the applications of those methods to the particular circumstances and, therefore, is not necessarily susceptible to partial analysis or summary description. Jefferies believes that its analyses must be considered as a whole. Considering any portion of Jefferies’ analyses or the factors considered by Jefferies, without considering all analyses and factors, could create a misleading or incomplete view of the process underlying the conclusion expressed in Jefferies’ opinion. In addition, Jefferies may have given various analyses more or less weight than other analyses, and may have deemed various assumptions more or less probable than other assumptions, so that the range of valuations resulting from any particular analysis described below should not be taken to be Jefferies’ view of the actual value of Diamondback or Endeavor. Accordingly, the conclusions reached by Jefferies are based on all analyses and factors taken as a whole and also on the application of Jefferies’ own experience and judgment.

In performing its analyses, Jefferies made numerous assumptions with respect to industry performance, general business, economic, monetary, regulatory, market and other conditions and other matters, many of which are beyond the parties’ and Jefferies’ control. The analyses performed by Jefferies are not necessarily indicative of actual values or actual future results, which may be significantly more or less favorable than suggested by such analyses. In addition, analyses relating to the per share value of Diamondback common stock do not purport to be appraisals or to reflect the prices at which Diamondback common stock may actually be sold or acquired. The analyses performed were prepared solely as part of Jefferies’ analysis of the fairness, from a financial point of view, of the Merger Consideration to be paid by Diamondback pursuant to the Merger Agreement, and were provided to the Board in connection with the delivery of Jefferies’ opinion.

The following is a summary of the material financial and comparative analyses performed by Jefferies in connection with Jefferies’ delivery of its opinion and that was presented to the Board on February 11, 2024. The

financial analyses summarized below include information presented in tabular format. In order to understand fully Jefferies’ financial analyses, the tables must be read together with the text of each summary. The tables alone do not constitute a complete description of the financial analyses. Considering the data described below without considering the full narrative description of the financial analyses, including the methodologies and assumptions underlying the analyses, could create a misleading or incomplete view of Jefferies’ financial analyses. The following summary does not purport to be a complete description of the financial analyses performed by Jefferies and factors considered in connection with Jefferies’ opinion. The following quantitative information, to the extent that it is based on market data, is based on market data as it existed on or before February, 9, 2024, and is not necessarily indicative of current or future market conditions.

Using the Diamondback projections for Endeavor prepared by Diamondback management, Jefferies performed a discounted cash flow analysis of Endeavor on a stand-alone basis (taking into account the Diamondback expected synergies). For purposes of this analysis, Jefferies used oil and gas price estimates provided by Diamondback management, which were $75.00/Bbl for oil and $3.00/MMBtu for natural gas (“Diamondback Management Pricing Estimates”). Jefferies calculated the unlevered free cash flows of Endeavor for the period commencing on January 1, 2024 through December 31, 2028, which it calculated as estimated earnings before interest, tax, depreciation and amortization (“EBITDA”), less capital expenditures and cash taxes. Jefferies then calculated the terminal value of Endeavor by applying a range of multiples of EBITDA in the terminal year of 4.2x to 5.2x, which range was selected by Jefferies in its professional judgment, to estimated terminal year EBITDA in 2028 for Endeavor, based on the Diamondback projections for Endeavor. The present values as of January 1, 2024 of the unlevered free cash flows and the terminal value of Endeavor were then calculated using discount rates ranging from 7.9% to 8.9%, which rates were based on the estimated weighted average cost of capital for Endeavor. Jefferies determined ranges of implied enterprise values for Endeavor by adding the range of present values as of January 1, 2024 it derived above for Endeavor’s unlevered free cash flows and terminal values. This analysis indicated a range of implied enterprise values of $26,249 million to $30,880 million, compared to the enterprise value of $26,000 million represented by the Merger Consideration.

Jefferies performed a net asset value analysis of Endeavor. Jefferies calculated indications of the present value of the unlevered, asset-level free cash flows that Endeavor could be expected to generate from existing proved developed reserves, development plans for proved undeveloped reserves and development of additional undeveloped reserves using the Diamondback projections for Endeavor (which take into account the Diamondback expected synergies) and Diamondback Management Pricing Estimates. Jefferies calculated indications of net present values as of January 1, 2024 of the asset-level free cash flows for Endeavor using discount rates ranging from 7.9% to 8.9%, which rates were based on the estimated weighted average cost of capital of Endeavor. Jefferies then calculated a range of implied equity values for Endeavor by (i) subtracting the present value as of January 1, 2024 of non-drilling and completion capital expenses, general and administrative expenses and cash taxes payable by Endeavor, in each case using estimates provided by Diamondback management, from the indications of the present value of the asset-level free cash flows calculated by Jefferies, (ii) adjusting for the present value as of January 1, 2024 of mark-to-market commodity hedges, and (iii) applying discount rates ranging from 7.9% to 8.9%, which reflects an estimate of Endeavor's weighted average cost of capital. This analysis implied a range of implied enterprise values for Endeavor from $30,373 million to $32,793 million, compared to the enterprise value of $26,000 million represented by the Merger Consideration.

Jefferies also performed a net asset value analysis of Endeavor using a discount rate based on industry requisite return levels of 10% to 13% (PV-10 to PV-13). This analysis implied a range of implied enterprise values for Endeavor from $23,414 million to $28,349 million, compared to the enterprise value of $26,000 million represented by the Merger Consideration.

With respect to Endeavor, Jefferies reviewed publicly available financial and stock market information of the following seven publicly traded natural gas and oil exploration and production companies that Jefferies in its

professional judgment considered generally relevant to Endeavor for purposes of its financial analyses (which are referred to as the “Endeavor Selected Companies”), and compared such information with similar financial data of Endeavor prepared and provided by Diamondback management to Jefferies:

Estimated EBITDA and levered free cash flow for the Endeavor Selected Companies was based on market data as of February 9, 2024 and utilizing First Call Pricing. For this analysis, Jefferies assumed First Call WTI Pricing for oil prices reflecting Wall Street research consensus estimates for 2024 and 2025 (which were $75.61 Bbl and $71.27 Bbl for oil in 2024 and 2025, respectively, and $3.09 MMBtu and $3.79 MMBtu for natural gas in 2024 and 2025, respectively), remaining constant at 2025 levels thereafter (“First Call Pricing”). This analysis indicated the following:

Using the reference ranges for the benchmarks set forth below, which ranges were selected based on the low, average, and high multiples of the Endeavor Selected Companies, and using metrics calculated by Jefferies based on the Diamondback projections for Endeavor utilizing First Call Pricing, Jefferies determined the ranges of implied total enterprise values set forth opposite the relevant benchmarks below and compared the results to the enterprise value of $26,000 million represented by the Merger Consideration.

Using publicly available information, Jefferies reviewed financial data to the extent available relating to two selected transactions announced in 2023 involving upstream companies in the Midland Basin with a transaction

value over $10 billion that Jefferies in its professional judgment considered generally relevant to Endeavor for purposes of its financial analyses, which are referred to as the “precedent transactions”.

The precedent transactions and the transaction dates, were as follows:

In its analysis, Jefferies derived multiples for each of the Precedent Transactions based on the following metrics:

This analysis indicated the following:

Using the reference ranges for the benchmarks set forth above, which ranges were selected by Jefferies in its professional judgment, and the Diamondback projections for Endeavor, Jefferies determined ranges of total implied enterprise values for Endeavor, utilizing First Call Pricing. At the direction of Diamondback management, Jefferies assumed a PV-10 value of $19.2 billion for proved developed reserves. This analysis indicated the ranges of implied enterprise values below.

No precedent transaction is identical to the Merger, and none of the target companies in the precedent transactions is identical to Endeavor. In evaluating the precedent transactions, Jefferies made numerous judgments and assumptions with regard to industry performance, general business, economic, market and financial conditions and other matters, many of which are beyond Endeavor’s, Diamondback’s, and Jefferies’ control. Mathematical analysis, such as determining the high, low and average is not in itself a meaningful method of using t he precedent transactions’ data.

Using the Diamondback projections for Diamondback based on Diamondback Management Pricing Estimates, Jefferies performed a discounted cash flow analysis of Diamondback on a stand-alone basis. Jefferies calculated the unlevered free cash flows of Diamondback for calendar years 2024 through 2028, which it calculated as estimated EBITDA, less capital expenditures, and cash taxes. Jefferies then calculated the terminal value of Diamondback by applying a range of multiples of EBITDA in the terminal year of 4.2x to 5.2x, which range was selected by Jefferies in its professional judgment, to estimated terminal year EBITDA in 2028 for

Diamondback, based on the Diamondback projections for Diamondback. The present values of the unlevered free cash flows and the terminal value of Diamondback were then calculated using discount rates ranging from 8.3% to 9.3%, which rates were based on the estimated weighted average cost of capital for Diamondback. Jefferies determined ranges of implied enterprise values for Diamondback by adding the range of present values it derived above for Diamondback’s unlevered free cash flows and terminal values. Jefferies then subtracted from the range of illustrative enterprise values it derived for Diamondback the estimated total net debt of Diamondback as of December 31, 2023 (adjusted for $28 million in senior notes repurchased in January 2024), and non-controlling interest in the aggregate amount of $8,939 million, as estimated and provided for Jefferies’ use by Diamondback management. Based on Diamondback’s fully diluted share count of 179.5 million shares as provided to Jefferies by Diamondback management, this analysis indicated a range of implied enterprise values per share of $124.06 to $155.95, compared to $153.51, the 30-day volume weighted average price of Diamondback common stock as of February 9, 2024, the last trading day prior to the announcement of the Merger Agreement.

Jefferies performed a net asset value analysis of Diamondback. Jefferies calculated indications of the present value of the unlevered, asset-level free cash flows that Diamondback could be expected to generate from existing proved developed reserves, development plans for proved undeveloped reserves and development of additional undeveloped reserves using Diamondback projections for Diamondback and Diamondback Management Pricing Estimates. Jefferies calculated indications of net present values of the asset-level free cash flows for Diamondback using discount rates ranging from 8.3% to 9.3%, reflecting an estimate of Diamondback’s weighted average cost of capital. Jefferies then calculated a range of implied equity values for Diamondback by subtracting from the range of the present value of the asset-level free cash flows calculated by Jefferies (i) the present value of general and administrative expenses and cash taxes payable by Diamondback using estimates provided by Diamondback management, applying discount rates ranging from 8.3% to 9.3%, reflecting an estimate of Diamondback’s weighted average cost of capital (ii) the present value of mark-to-market commodity hedges, applying discount rates ranging from 8.3% to 9.3%, and (iii) Diamondback’s net debt of $5,140 million as of December 31, 2023 (exclusive of the net debt of Diamondback’s subsidiary Viper Energy, Inc.), and adjusting the result for Diamondback’s 51% equity ownership interest in Viper which Jefferies valued at $2,876 million based on Viper’s closing stock price on February 8, 2024 of $31.71 per share and Diamondback’s ownership of 90.7 million shares, as provided by Diamondback management. Based on Diamondback’s fully diluted share count of 179.5 million shares as provided to Jefferies by Diamondback management, this analysis indicated a range of implied equity values per share for Diamondback common stock of $176.54 to $189.69, compared to $153.51, the 30-day volume weighted average price of Diamondback common stock as of February 9, 2024, the last trading day prior to the announcement of the Merger Agreement.

Jefferies also performed a net asset value analysis of Diamondback using a discount rate based on industry requisite return levels of 10% to 13% (PV-10 to PV-13). This analysis indicated a range of implied equity values per share for Diamondback common stock of $139.79 to $168.48, compared to $153.51, the 30-day volume weighted average price of Diamondback common stock as of February 9, 2024, the last trading day prior to the announcement of the Merger Agreement.

With respect to Diamondback, Jefferies reviewed publicly available financial and stock market information of the following seven publicly traded natural gas and oil exploration and production companies that Jefferies in its professional judgment considered generally relevant to Diamondback for purposes of its financial analyses (which are referred to as the “Diamondback Selected Companies”), and compared such information with similar financial data of Diamondback prepared and provided by Diamondback management to Jefferies:

In its analysis, Jefferies derived multiples for the Diamondback Selected Companies from the following metrics:

Estimated EBITDA and levered free cash flow for the Diamondback Selected Companies was based on market data and Capital IQ consensus estimates as of February 9, 2024. For this analysis, Jefferies assumed First Call Pricing. This analysis indicated the following:

Using the reference ranges for the benchmarks set forth below, which ranges were selected based on the low, average, and high multiples of the Diamondback Selected Companies, and using metrics calculated by Jefferies based on the Diamondback projections for Diamondback utilizing First Call Pricing, Jefferies determined the ranges of implied total enterprise value for Diamondback set forth opposite the relevant benchmark below.

Jefferies then calculated estimated equity value ranges for Diamondback by adjusting the ranges of implied total enterprise value for Diamondback by consolidated Diamondback net debt of $6,207 million (including net debt of Viper) and non-controlling interest of $2,732 million. Based on Diamondback’s fully diluted share count of 179.5 million shares as provided to Jefferies by Diamondback management, this analysis indicated the ranges of implied equity value and equity value per share set forth opposite the relevant benchmark below, compared to $153.51, the 30-day volume weighted average price of Diamondback Common Stock as of February 9, 2024, the last trading day prior to the announcement of the Merger Agreement:

Jefferies’ opinion was one of many factors taken into consideration by the Board in making its determination to approve the proposed transactions contemplated by the Merger Agreement and should not be considered determinative of the view of the Board with respect to the proposed transactions contemplated by the Merger Agreement.

Jefferies was selected by the Board based on Jefferies’ qualifications, expertise and reputation. Jefferies is an internationally recognized investment banking and advisory firm. Jefferies, as part of its investment banking business, is regularly engaged in the valuation of businesses and securities in connection with mergers and acquisitions, negotiated underwritings, competitive biddings, secondary distributions of listed and unlisted securities, private placements, financial restructurings and other financial services.

Pursuant to the engagement letter dated as of January 20, 2024 and amended as of February 2, 2024, Jefferies was engaged by Diamondback to act as financial advisor to Diamondback in connection with a possible series of related acquisitions by Diamondback of all or substantially all of the assets of Endeavor. Pursuant to Jefferies’ engagement as financial advisor to Diamondback and as a result of Diamondback’s entry into the Merger Agreement and other transactions contemplated therein, Jefferies will receive a fee for its services. Diamondback has agreed to pay Jefferies a transaction fee of $30.0 million, of which $3.0 million was payable upon delivery of Jefferies' opinion, and the remainder of which is payable upon the closing of the Merger contemplated by the Merger Agreement. No portion of the opinion fee was contingent on the conclusion expressed in Jefferies’ opinion. Diamondback has agreed to reimburse Jefferies for certain out-of-pocket expenses (including fees and expenses of its counsel) and to indemnify Jefferies and its affiliates against certain liabilities arising out of or in connection with the services rendered and to be rendered by Jefferies under its engagement. In the past, Jefferies has provided financial advisory and financing services to Diamondback and may continue to do so, and has received, and may receive, fees for the rendering of such services. During the two years prior to the date of its opinion, Jefferies received fees in the aggregate amount of $6.5 million from Diamondback in connection with acting as sole financial advisor in Diamondback’s acquisition of certain premium leasehold of interests and related assets of Lario Oil & Gas Company in January 2023. In the ordinary course of its business, Jefferies and its affiliates may trade or hold securities of Diamondback or Endeavor and/or their respective affiliates for its own account and for the accounts of its customers and, accordingly, may at any time hold long or short positions in those securities. In addition, Jefferies may seek to, in the future, provide financial advisory and financing services to Diamondback, Endeavor or entities that are affiliated with Diamondback or Endeavor, for which Jefferies would expect to receive compensation. Jefferies’ opinion may not be used or referred to by Diamondback, or quoted or disclosed to any person in any manner, without Jefferies’ prior written consent.

Subject to the terms and conditions set forth in the Merger Agreement, Merger Sub I will merge with and into Endeavor, with Endeavor surviving the First Merger and becoming a wholly owned subsidiary of Diamondback. Immediately following the First Merger, the First Surviving Company will merge with and into Merger Sub II, with Merger Sub II surviving the Second Merger and continuing (immediately following the Second Merger) as a wholly owned subsidiary of Diamondback. As a result of the Merger, Diamondback will acquire 100% of the Endeavor Interests.

If the Merger is completed, the aggregate consideration in exchange for the Endeavor Interests will be (i) cash consideration of $8.0 billion, subject to adjustments in accordance with the terms of the Merger Agreement, and (ii) 117,267,069 shares of common stock. For additional information, see the section entitled “The Merger Agreement—Merger Consideration.”

The Merger will have the effects set forth in the Merger Agreement, the certificates of merger filed in connection with the Closing and in the relevant provisions of Texas and Delaware law. At the First Merger Effective Time, all the property, rights, privileges, powers and franchises of each of Merger Sub I and Endeavor will vest in the First Surviving Company, and all debts, liabilities, obligations, restrictions, disabilities and duties of each of Merger Sub I and Endeavor will become the debts, liabilities, obligations, restrictions, disabilities and duties of the First Surviving Company. At the Merger Effective Time, all the property, rights, privileges, powers

and franchises of each of Merger Sub II and the First Surviving Company will vest in the Surviving Company, and all debts, liabilities, obligations, restrictions, disabilities and duties of each of Merger Sub II and the First Surviving Company will become the debts, liabilities, obligations, restrictions, disabilities and duties of the Surviving Company.

Diamondback currently anticipates that the Merger will be completed in the fourth quarter of 2024, but cannot be certain when or if the conditions to the Merger will be satisfied or, to the extent permitted, waived. The Merger cannot be completed until the conditions set forth in the Merger Agreement are satisfied (or, to the extent permitted, waived).

Prior to the Closing Date, Diamondback is required to take all necessary actions to cause four individuals mutually agreed by Diamondback and Endeavor in writing prior to the Closing (with any replacement thereto similarly mutually agreed) to be appointed to the Board immediately following the Merger Effective Time. As of the date of this proxy statement, Charles Meloy and Lance Robertson are expected to be designated as two of the new directors and the parties have not determined the identity of the other two directors.

The Stockholders Agreement will provide the Endeavor Stockholders with the right to propose for nomination four directors for election to the Board if they beneficially own at least 25% of the outstanding shares of our common stock, two directors if they beneficially own at least 20% but less than 25% of the outstanding shares of our common stock, and one director if they beneficially own at least 10% but less than 20% of the outstanding shares of our common Stock, in each case subject to certain qualification requirements for such directors. For additional information, see the section entitled “The Stockholders Agreement.”

The Stockholders Agreement to be entered into in connection with the Closing, in addition to entitling the Endeavor Stockholders to nominate for election directors to the Board, will grant the Endeavor Stockholders with certain shelf, demand and piggyback registration rights, including that, if not previously filed, Diamondback will file a shelf registration statement to cover the resale of the shares of common stock issued to the Endeavor Stockholders as Common Stock Consideration. Under the terms of the Stockholders Agreement, the Endeavor Stockholders will be subject to certain standstill, voting and transfer restrictions, and Diamondback will be restricted from taking certain limited actions without the consent of the holders of a majority of the shares of common stock held by the Endeavor Stockholders. For additional information, see the section entitled “The Stockholders Agreement.”

If the approval of the Diamondback Stockholder Approval is not received, or if the Merger is not completed for any other reason, then the Merger Agreement may be terminated. In the event of a termination, the Merger Agreement will be void and have no effect, and there will not be any liability or obligation on the part of any party, except that:

If the Merger Agreement is terminated under specified circumstances, Diamondback may be required to pay Endeavor a termination fee of $1,400,000,000. In the event the Merger Agreement is terminated because of a failure to the receive the Diamondback Stockholder Approval, and the aforementioned $1,400,000,000 termination fee is not otherwise payable under the terms of the Merger Agreement, Diamondback is required to reimburse Endeavor for its transaction related expenses, subject to a cap of $260,000,000. The payment of this

reimbursement expense will be credited against any termination fee that is subsequently payable by Diamondback. These payments are Endeavor’s sole and exclusive remedy, except in the case of a Willful and Material Breach or fraud, for any claims arising out of the Merger Agreement, together with any costs and expenses incurred by Endeavor in enforcing payment of such payments. In no event will Diamondback be required to pay to Endeavor more than one termination fee.

For additional information, see the section entitled “The Merger Agreement—Termination Fees.”

Diamondback anticipates that the total amount of funds necessary to satisfy the Obligations will be approximately $8.2 billion. Diamondback expects that these amounts will be funded through some or all of (i) the takeout facility, (ii) cash on hand and/or (iii) the proceeds that Diamondback intends to obtain from other financings or offerings of debt securities in lieu of borrowing under the bridge facility. Pursuant to the Bridge Commitment Letter for the bridge facility, Diamondback received commitments for an aggregate principal amount of $8.0 billion in aggregate principal amount of senior unsecured term bridge loans, the availability of which was and is subject to reduction upon the consummation of the Permanent Financing pursuant to the terms set forth in the Bridge Commitment Letter. On February 29, 2024, Diamondback entered into the $1.5 billion takeout facility and pursuant to the terms of the Bridge Commitment Letter, the commitments with respect to the bridge facility were reduced to $6.5 billion.

Pursuant to the takeout facility, Diamondback received commitments for the extension of a senior unsecured term loan in an aggregate principal amount not to exceed $1.5 billion, consisting of a 1 year, $1,000,000,000 Tranche A and a 2 year, $500,000,000 Tranche B. The commitments under the takeout facility are subject to customary closing conditions. The borrower under the takeout facility is Diamondback E&P LLC, a subsidiary of Diamondback and Diamond guarantees the takeout facility.

The commitments under the takeout facility terminate upon the earliest to occur of (i) the date that is five business days after the first anniversary of the Closing Date (subject, to two three-month extensions pursuant to the extensions of the Outside Date (as defined below)), (ii) the funding of the loans thereunder on the Closing Date, (iii) the occurrence of the Closing Date without the funding of the loans thereunder and (iv) the date that the Merger Agreement is terminated by Diamondback in accordance with the terms of the Merger Agreement.

Diamondback intends to obtain additional financing or issue debt securities in lieu of utilizing the remaining portion of the bridge facility; however, there is no assurance that such alternative arrangements will be available on acceptable terms or at all. If the bridge facility is utilized there can be no assurance that any replacement or supplemental financing in lieu of or to refinance the bridge facility will be available to Diamondback on acceptable terms or at all. Diamondback’s ability to obtain additional debt financing, including financing to refinance, replace or supplement the bridge facility, will be subject to various factors, including market conditions and operating performance.

The funding under either the Bridge Commitment Letter or the takeout facility, as applicable, is subject to customary closing conditions, including conditions that do not relate directly to the conditions to the closing of the Merger in the Merger Agreement.

The proceeds of the loans under the takeout facility will be used to provide a portion of the debt financing required to fund the cash consideration for the Merger, to refinance certain indebtedness of Endeavor, which is required to consummate the proposed transaction and/or for the payment of related fees and expenses.

The interest rate per annum applicable to the loans under the takeout facility are, at Diamondbacks’ option, equal to either a base rate or a Term SOFR (or successor) rate plus an applicable margin, which may (in the case of Term SOFR loans) range, in the case of Tranche A loans, from 1.125% to 2.000%, and, in the case of Tranche B loans, from 1.250% to 2.125%, in each case based on Diamondback’s public debt rating. The applicable margin on base rate loans is 1.00% less than the corresponding margin on Term SOFR (or successor rate) based loans.

The maturity of the Tranche A will be one year after the Closing Date and the maturity of the Tranche B will be two years after the Closing date. Once advanced, the outstanding principal amount of the term loans will be due in full on the respective maturity dates. The takeout facility is not subject to mandatory prepayment. Diamondback may prepay all or any portion of the term loans under the takeout facility prior to maturity without premium or penalty, subject to reimbursement of any Term SOFR breakage costs of the lenders.

The obligation of the lenders to fund the loans under the takeout facility on the Closing Date is subject, among other things, to:

For more information, see “The Merger Agreement—Financing.”

The takeout facility contains customary affirmative and negative covenants and events of default (including relating to a change of control) that are customary for similar facilities for similarly rated borrowers. Among other things, such negative covenants restrict, subject to certain exceptions, the ability of Diamondback and its subsidiaries, to create liens, incur indebtedness (solely with respect to any non-guarantor subsidiary of Diamondback), mergers or consolidations, or change the nature of their business. In addition, the takeout facility contains financial covenants which require that Diamondback’s consolidated total net debt to capitalization ratio may not exceed 65% on the last day of any of its fiscal quarters.

Diamondback and Endeavor are not currently aware of any other material governmental approvals, consents, registrations, permits, expirations or terminations of waiting periods, authorizations or other confirmations that are required prior to the parties’ completion of the Merger other than those described below. If additional approvals, consents, registrations, permits, expirations or terminations of waiting periods, authorizations and other confirmations are required to complete the transaction, Diamondback and Endeavor intend to seek such approvals, consents, registrations, permits, expirations or terminations of waiting periods, authorizations and other confirmations.

Diamondback and Endeavor expect to complete the Merger in the fourth quarter of 2024. Although Diamondback and Endeavor believe that they will receive the required approvals, consents, registrations, permits, expirations or terminations of waiting periods, authorizations and other confirmations to complete the transaction, neither can give any assurance as to the timing of these approvals, consents, registrations, permits, expirations or terminations of waiting periods, authorizations and other confirmations as to Diamondback’s and Endeavor’ ultimate ability to obtain such approvals, consents, registrations, permits, expirations or terminations of waiting periods, authorizations and other confirmations (or any additional approvals, consents, registrations, permits, expirations or terminations of waiting periods, authorizations or other confirmations which may otherwise

become necessary) or that such approvals, consents, registrations, permits, expirations or terminations of waiting periods, authorizations or other confirmations will be obtained on terms and subject to conditions satisfactory to Diamondback and Endeavor. The receipt of the regulatory approvals (as described herein) is a condition to the obligation of each of Diamondback and Endeavor to complete the Merger.

The Merger is subject to the requirements of the HSR Act and the related rules and regulations, which provide that certain transactions may not be completed until notification and report forms have been furnished to the DOJ and the FTC and until certain waiting periods have been terminated or have expired. The HSR Act requires Diamondback and Endeavor to observe a 30-calendar-day waiting period after the submission of their respective HSR notification and report forms before consummating their transactions. The waiting period may be shortened if the reviewing agency grants “early termination” of the waiting period (although the practice of granting early termination has been temporarily suspended by the FTC and DOJ), or lengthened if the acquiring person (here Diamondback) voluntarily withdraws and refiles to allow a second 30-calendar-day waiting period, or if the reviewing agency issues a request for additional information or documentary material (the “Second Request”) prior to the expiration of the initial waiting period. If a Second Request is issued, the parties must observe a second 30-calendar-day waiting period, which begins to run only after each of the parties has substantially complied with the Second Request. It is also possible that Diamondback and Endeavor could enter into a timing agreement with the FTC or DOJ that could affect the timing of the consummation of the Merger.

Diamondback and Endeavor each filed the required notification and report forms under the HSR Act on February 26, 2024. The 30-day waiting period following the parties’ filings expires on March 27, 2024, unless extended or earlier terminated.

For a further description of Diamondback’s and Endeavor’s respective obligations under the Merger Agreement with respect to regulatory approvals, see the section entitled “The Merger Agreement—Covenant and Agreements—Efforts to Complete the Merger.”

Diamondback has agreed to use its reasonable best efforts to cause the shares of common stock to be issued as Common Stock Consideration to be approved for listing on Nasdaq, subject to official notice of issuance, prior to the First Merger Effective Time.

On February 28, 2024, Plymouth County Retirement Association and Kenneth Webb, purported stockholders of Diamondback, filed a purported class action complaint in the Court of Chancery of the State of Delaware, captioned Plymouth County Retirement Association and Kenneth Webb v. Travis Stice et al., Docket No. 2024-0183 (the “Webb Action”), against Diamondback and the Board. The Webb Action alleges, among other things, that the Board breached its fiduciary duties to Diamondback stockholders by approving the Stockholders Agreement. The Webb Action seeks, among other things, class certification, enjoinment of the enforcement of certain provisions of the Stockholders Agreement, including the Endeavor Stockholders’ voting obligations and certain stock transfer restrictions thereunder, and an award of attorneys’ fees and costs. Diamondback believes that the allegations in the Webb Action are without merit. As a result of the amendment to the Merger Agreement entered into on March 18, 2024, which amends and restates the form of Stockholders Agreement, the plaintiffs have agreed to dismiss the Webb Action.

As of March 15, 2024, Diamondback was not aware of the filing of other lawsuits challenging the Merger Agreement, the Stockholders Agreement, the transactions contemplated thereby or the proxy statement; however, Diamondback may become subject to other lawsuits in the future relating to such matters. See the section entitled “Risk Factors” for additional information and risks regarding any such potential litigation.

The following summary describes certain material provisions of the Merger Agreement. This summary is not complete and is qualified in its entirety by the Merger Agreement and the Letter Agreement, amending the Merger Agreement, which are attached to this proxy statement as Annex A-1 and Annex A-2 respectively, and which constitute part of this proxy statement. We encourage you to read carefully the Merger Agreement in its entirety because this summary may not contain all of the information about the Merger Agreement that is important to you. The rights and obligations of the parties to the Merger Agreement are governed by the express terms of the Merger Agreement and not by this summary or any other information contained in this proxy statement.

The representations, warranties, covenants and agreements described below and included in the Merger Agreement were made only for purposes of the Merger Agreement as of specific dates, were solely for the benefit of the parties to the Merger Agreement (except as otherwise specified therein) and may be subject to important qualifications, limitations and supplemental information agreed to by the parties in connection with negotiating the terms of the Merger Agreement. In addition, the representations and warranties may have been included in the Merger Agreement for the purpose of allocating contractual risk between the parties rather than to establish matters as facts and may be subject to standards of materiality applicable to such parties that differ from those applicable to investors. Investors and security holders are not third-party beneficiaries under the Merger Agreement and should not rely on the representations, warranties, covenants and agreements or any descriptions thereof as characterizations of the actual state of facts or condition of the parties thereto, or any of their respective affiliates or businesses. Moreover, information concerning the subject matter of the representations and warranties may change after the date of the Merger Agreement. In addition, you should not rely on the covenants and agreements in the Merger Agreement as actual limitations on the respective businesses of the parties because the parties to the Merger Agreement may take certain actions that are either expressly permitted in the confidential disclosure schedule to the Merger Agreement or as otherwise consented to by the appropriate party, which consent may be given without prior notice to the public. The Merger Agreement is described below, and included as Annex A-1 hereto (along with the Letter Agreement, amending the Merger Agreement, as Annex A-2), only to provide you with information regarding its terms and conditions and not to provide any other factual information regarding the parties, or their respective businesses. Accordingly, the representations, warranties, covenants and other agreements in the Merger Agreement should not be read alone, and you should read the information provided elsewhere in this document and in the filings that Diamondback has made or will make with the SEC. See the section entitled “Where You Can Find More Information.”

Subject to the terms and conditions set forth in the Merger Agreement, Merger Sub I will merge with and into Endeavor, with Endeavor surviving the First Merger and becoming a wholly owned subsidiary of Diamondback. Immediately following the First Merger, the First Surviving Company will merge with and into Merger Sub II, with Merger Sub II surviving the Second Merger and continuing (immediately following the Second Merger) as a wholly owned subsidiary of Diamondback. As a result of the Merger, Diamondback will acquire 100% of the Endeavor Interests. As mentioned previously, the First Merger and the Second Merger are collectively referred to herein as the “Merger.”

It is intended that the First Merger and the Second Merger, taken together, will constitute an integrated transaction for U.S. federal income tax purposes that will qualify as a “reorganization” within the meaning of Section 368(a) of the Code (the “Reorganization Treatment”).

We collectively refer to Diamondback and the surviving entity, after giving effect to the Merger, together with their subsidiaries, as the “combined company.”

In order to effectuate the First Merger, a merger certificate will be filed in each of Texas and Delaware. The later of the date and time at which the Texas merger certificate or the Delaware merger certificate for the First Merger, as applicable, becomes effective, or such later date and time as may be agreed in writing by Diamondback and Endeavor and specified in the Texas merger certificate and the Delaware merger certificate for the First Merger, as applicable, will be the effective time of the First Merger, referred to in this proxy statement as the “First Merger Effective Time.”

In order to effectuate the Second Merger, a merger certificate will be filed in each of Texas and Delaware. The later of the date and time at which the Texas merger certificate or the Delaware merger certificate for the Second Merger, as applicable, becomes effective, or such later date and time as may be agreed in writing by Diamondback and Endeavor and specified in Texas merger certificate and the Delaware merger certificate for the Second Merger, as applicable, will be the effective time of the Second Merger, referred to in this proxy statement as the “Merger Effective Time.”

The closing of the First Merger will take place at the offices of Paul, Weiss, Rifkind, Wharton & Garrison LLP, 1285 Avenue of the Americas, New York, New York, 10019 on the third business day after the satisfaction (other than those conditions that by their terms are to be satisfied at the Closing, but subject to the satisfaction or, to the extent permitted by applicable law, waiver of those conditions) of the closing conditions described below under “—Conditions to the Merger” unless another date, time or place agreed to in writing by Diamondback and Endeavor or via the electronic transfer of documents and signature pages, should the parties choose to forego a physical Closing.

The Merger will have the effects set forth in the Merger Agreement, the certificates of merger filed in connection with the Closing and in the relevant provisions of the Texas Business Organizations Code (the “TBOC”) and the Delaware Limited Liability Company Act (the “DLLCA”). At the First Merger Effective Time, all the property, rights, privileges, powers and franchises of each of Merger Sub I and Endeavor will vest in the First Surviving Company, and all debts, liabilities, obligations, restrictions, disabilities and duties of each of Merger Sub I and Endeavor will become the debts, liabilities, obligations, restrictions, disabilities and duties of the First Surviving Company. At the Merger Effective Time, all the property, rights, privileges, powers and franchises of each of Merger Sub II and the First Surviving Company will vest in the Surviving Company, and all debts, liabilities, obligations, restrictions, disabilities and duties of each of Merger Sub II and the First Surviving Company will become the debts, liabilities, obligations, restrictions, disabilities and duties of the Surviving Company.

At the First Merger Effective Time (i) the certificate of formation of Endeavor will continue unchanged as the certificate of formation of the First Surviving Company and (ii) the limited liability company agreement of Endeavor will be amended and restated in its entirety to read as the limited liability company agreement of Merger Sub I in effect immediately prior to the First Merger Effective Time (with all references to Merger Sub I and the TBOC therein revised to refer to the First Surviving Company and the DLLCA, respectively), in each case until thereafter amended as provided therein or by applicable law.

At the Merger Effective Time (i) the certificate of formation of Merger Sub II will continue unchanged as the certificate of formation of the Surviving Company and (ii) the limited liability company agreement of Merger Sub II in effect as of immediately prior to the Merger Effective Time will be amended and restated in its entirety to read as the limited liability company agreement of the Surviving Company in the form attached as Exhibit D to the Merger Agreement, in each case until thereafter amended as provided therein or by applicable law.

Prior to the Closing Date, Diamondback must take all necessary actions to cause four individuals mutually agreed by Endeavor and Diamondback in writing prior to the Closing (with any replacement thereto similarly mutually agreed) to be appointed to the Board immediately following the Merger Effective Time. Such designees must meet the criteria for service on the Board under applicable law, Nasdaq rules and the Stockholders Agreement (as if the latter were in effect as of the time of such nomination). For additional information, see the section entitled “The Stockholders Agreement” and Annex B to this proxy statement.

The parties will take all actions necessary such that the officers of Merger Sub I immediately prior to the First Merger Effective will be the officers of the First Surviving Company following the completion of the First Merger, and that the officers of the First Surviving Company immediately prior to the Merger Effective

Date will be the officers of the Surviving Company following the completion of the Second Merger, with each to hold office until their respective successors are duly elected or appointed and qualified or until their earlier death, resignation or removal in accordance with applicable law and the applicable limited liability company agreement of the First Surviving Company and the limited liability company agreement of the Surviving Company, as applicable.

If the Merger is completed, pursuant to and subject to the terms and conditions of the Merger Agreement, the Endeavor Interests will be converted into the right to receive, in the aggregate, (i) cash consideration of $8.0 billion, subject to adjustments in accordance with the terms of the Merger Agreement (as described in more detail below), and (ii) 117,267,069 shares of common stock.

The Cash Consideration to be paid in connection with the Merger is subject to certain adjustments. The Cash Consideration is equal to (i) $8.0 billion, plus (ii) the Permitted Distribution Amount, less (iii) the Make-Whole Amount, less (iv) Leakage, less (v) Specified Permitted Leakages and less (vi) the Net Debt Position.

Prior to the Closing, prongs (ii) through (vi) above (the “Closing Adjustment”) will be calculated in accordance with the terms of the Merger Agreement in a closing statement delivered by Endeavor to Diamondback prior to the Closing Date and the Cash Consideration paid at Closing will be based on such closing statement. Following the Closing, prongs (ii) through (vi) above (the “Post-Closing Adjustment”) will be calculated in accordance with the terms of the Merger Agreement in a post-closing statement delivered by Diamondback to the Company Representative. Each of the Closing Adjustment and the Post-Closing Adjustment are subject to certain review and agreement rights of both Diamondback and Endeavor (or the Company Representative with respect to the Post-Closing Adjustment). Further, the Post-Closing Adjustment is subject to the review of, and determination by, an independent, third-party accountant in the event that Diamondback and the Company Representative cannot reach an agreement to its value. If the Post-Closing Adjustment is greater than the Closing Adjustment, then Diamondback will pay such a difference to the holders of the Endeavor Interests in cash. If the Post-Closing Adjustment is less than the Closing Adjustment, then the Company Representative will pay such a difference to Diamondback in cash. If both the Closing Adjustment and the Post-Closing Adjustment are the same, then no adjustment payments will be made by either Diamondback or Endeavor.

For the purposes of the above calculations:

“Permitted Distribution Amount” means the dollar amount that is equal to the product of (i) the total dividends per share declared by Diamondback per share of common stock following the date of the Merger Agreement and prior to the Closing Date and with a record date that is prior to the Closing Date (other than Diamondback’s regular quarterly dividend to be declared and paid between the date of the Merger Agreement and March 31, 2024 in an amount not to exceed $3.10 per share of common stock) and (ii) 117,267,069 (i.e. the number of shares of common stock forming the Common Stock Consideration).

“Make-Whole Amount” means the prepayment premiums, penalties, breakage costs or other similar obligations required for (i) the termination of Endeavor’s existing credit agreement and (ii) the discharge of Endeavor’s existing senior notes in accordance with the terms of the Merger Agreement.

“Leakage” means any of the following, but excluding Permitted Leakage: (i) any dividend or distribution (whether in cash or in kind) declared, paid or made by Endeavor or any of its subsidiaries to any person other than a wholly owned subsidiary of Endeavor; (ii) any redemption or purchase of equity interests by Endeavor or any of its subsidiaries other than to, or in respect of equity interests held solely by, Endeavor or a wholly owned subsidiary of Endeavor; (iii) any payments (including management, monitoring, advisory or other fees) made or other economic benefits given by Endeavor or any of its subsidiaries to any of Endeavor’s restricted affiliates (as defined below) (other than payments required to be made under the terms of certain specified contracts, as in effect on the date of the Merger Agreement); (iv) any assets transferred to any restricted affiliate of Endeavor by Endeavor or any of its subsidiaries (other than pursuant to certain specified transfers as in effect on the date of the Merger Agreement); (v) any

liability of any restricted affiliate of Endeavor, which is assumed, incurred or indemnified by Endeavor or its subsidiaries (excluding any preexisting employment or director indemnification agreements or arrangements with any employee, officer or director); (vi) any lending or guaranteeing by Endeavor or any of its subsidiaries of any amount owed by any restricted affiliate of Endeavor, and any waiver or agreement to waive any amount owed to Endeavor or any of its subsidiaries by any restricted affiliate of Endeavor; and (vii) the agreement by Endeavor or any of its subsidiaries to do any of the matters or pay any amounts referred to in the foregoing clauses (i) through (vi). Endeavor’s “restricted affiliates” mean (a) the Endeavor Stockholders, (b) any affiliate of the Endeavor Stockholders and (c) any immediate family members of the Endeavor Stockholders or their controlling persons, including Mr. Stephens, his immediate family members or any of their respective affiliates, but excluding, in each case, Endeavor and its subsidiaries.

“Permitted Leakages” means (i) any payment made or agreed to be made by Endeavor or any of its subsidiaries at the express written request (or with the express prior written consent) of Diamondback; (ii) any payment made or agreed to be made in respect of salary, fees, bonuses or other monetary benefit paid to employees of Endeavor or its subsidiaries and, to the extent performing services in respect of the business of Endeavor or any of its subsidiaries, in each case, in the ordinary course of business and consistent with past practice; (iii) any payment made, or agreed to be made, by Endeavor or any of its subsidiaries in relation to the premiums for any preexisting insurance policies with respect to directors and officers liability; (iv) the distribution of up to $690,000,000; (v) the distribution of the Permitted Distribution Amount; (vi) any payments made in the ordinary course of business pursuant to certain permitted oil and gas arrangements (including payments made in respect of production burdens); and (vii) any taxes incurred by Endeavor or any of its subsidiaries in connection with any of the transactions or matters described in the foregoing clauses.

“Specified Permitted Leakages” means (i) the distribution of up to $690,000,000 and (ii) the distribution of the Permitted Distribution Amount.

“Net Debt Position” means the dollar amount agreed between the parties that represents (i) the indebtedness of Endeavor and its subsidiaries, taken as a whole, as of December 31, 2023, minus (ii) the cash and cash equivalents of Endeavor and its subsidiaries, taken as a whole, as of December 31, 2023.

At the First Merger Effective Time, the following will occur automatically by virtue of the First Merger:

As of the First Merger Effective Time, the Endeavor Interests will be cancelled and holders of the Endeavor Interests will cease to have any associated rights, except the right to receive their portion of the Merger Consideration in accordance with the terms of the Merger Agreement.

At the Merger Effective Time, the following will occur automatically by virtue of the Second Merger:

The obligations of each of Diamondback, the Merger Subs and Endeavor to complete the Merger are subject to the mutual satisfaction or waiver of various conditions at or prior to the First Merger Effective Time, including the following:

In addition, the obligations of Diamondback and the Merger Subs to complete the Merger are subject to the satisfaction or waiver of various conditions at or prior to the First Merger Effective Time, including the following:

In addition, the obligation of Endeavor to complete the Merger are subject to satisfaction or waiver of various conditions at or prior to the First Merger Effective Time, including the following:

The Merger Agreement may be terminated at any time prior to the First Merger Effective Time (with any termination by Diamondback also being an effective termination by the Merger Subs):

If the Merger Agreement is terminated as described in “—Termination of the Merger Agreement” above, the Merger Agreement will be void and have no effect, and there will not be any liability or obligation on the part of any party, except that:

The Merger Agreement provides that Diamondback will pay Endeavor a termination fee of $1,400,000,000 in cash in connection with a termination of the Merger Agreement under the following circumstances:

Additionally, if the Merger Agreement is terminated because of failure to receive the Diamondback Stockholder Approval and the termination fee is not payable pursuant to the above, then Diamondback is required to reimburse Endeavor for all reasonable out-of-pocket fees and expenses incurred or paid by Endeavor, the Company Representative or any of their affiliates in connection with the authorization, preparation, investigation, negotiation, execution and performance of the Merger Agreement and the transactions contemplated thereby, including all due diligence and financing costs, filing fees, printing fees and fees and expenses of law firms, commercial banks, investment banking firms, accountants, experts and consultants, subject to a cap of $260,000,000.

If Diamondback fails to promptly pay any amounts due pursuant to the termination fee and expense reimbursement provisions, and, in order to obtain such payment, Endeavor commences a suit that results in a judgment against Diamondback for such amounts or any portion thereof, Diamondback must pay Endeavor its reasonable and documented out-of-pocket costs and expenses (including reasonable attorneys’ fees and expenses) in connection with such suit, together with interest on the amounts due pursuant to the termination fee and expense reimbursement provisions from the date such payment was required to be made until the date of payment at the prime lending rate as published in The Wall Street Journal in effect on the date such payment was required to be made.

The payment of the expense reimbursement will be credited against any termination fee that may subsequently become payable by Diamondback. The termination fee and expense reimbursement are Endeavor’s sole and exclusive remedy, except in the case of a Willful and Material Breach or fraud, for any loss suffered, directly or indirectly, as a result of the failure of the Merger or the other transactions to be consummated, the termination of the Merger Agreement, any liabilities or obligations arising under the Merger Agreement, or any claims or actions arising out of or relating to any breach, termination or failure of or under the Merger Agreement. In no event will Diamondback be required to pay to Endeavor more than one termination fee.

Endeavor has agreed to certain covenants in the Merger Agreement restricting the conduct of its business between the date of the Merger Agreement and the Closing Date.

Endeavor has agreed that, except (i) for certain scheduled exceptions, (ii) as required in the event of an emergency to protect life or protect against an imminent and substantial threat to property or the environment, (iii) as required as required by law, (iv) as expressly required or expressly permitted by the Merger Agreement or (v) as otherwise consented to in writing by Diamondback (such consent not to be unreasonably withheld, delayed or conditioned), it will, and will cause its subsidiaries to:

Diamondback has agreed to certain covenants in the Merger Agreement restricting the conduct of its business between the date of the Merger Agreement and the Closing Date.

Diamondback has agreed that, except (i) for certain scheduled exceptions, (ii) as required in the event of an emergency to protect life or protect against an imminent and substantial threat to property or the environment, (iii) as required as required by law, (iv) as expressly required or expressly permitted by the Merger Agreement or (v) as otherwise consented to in writing by Endeavor (such consent not to be unreasonably withheld, delayed or conditioned), it will, and will cause its subsidiaries to:

As promptly as practicable after Diamondback obtains confirmation from the SEC or its staff, orally or in writing, that it does not have any further comments (or it does not intend to review) the proxy statement, but no later than in 30 days, Diamondback has agreed to duly call, give notice of, convene and hold a meeting of its stockholders for the purpose of seeking the approval of the Stock Issuance Proposal and the Charter Amendment Proposal (the “stockholders meeting”).

Diamondback may postpone or adjourn the stockholders meeting solely (i) with the prior written consent of Endeavor; (ii) (A) due to the absence of a quorum at the time the stockholder meeting is otherwise scheduled (provided, that Diamondback must use its reasonable best efforts to obtain such a quorum as promptly as practicable), (B) if Diamondback believes in good faith that such adjournment or postponement is reasonably necessary to allow reasonable additional time to solicit additional proxies necessary for the Diamondback Stockholder Approval, whether or not a quorum is present, (C) to allow reasonable additional time for the filing and mailing of any supplemental or amended disclosure that the Board has determined in good faith after consultation with outside legal counsel is necessary under applicable law and for such supplemental or amended disclosure to be disseminated and reviewed by Diamondback stockholders prior to the stockholders meeting, or (D) to the extent such postponement or adjournment of the stockholders meeting is required by an order issued by any court or other governmental entity of competent jurisdiction in connection with the Merger Agreement; provided, (x) that Diamondback may not postpone or adjourn the stockholders meeting pursuant to clause (ii)(A) and/or clause (ii)(B) for a period exceeding twenty business days without the prior written consent of Endeavor, and (y) if the stockholder meeting is postponed, Diamondback must reconvene the stockholder meeting at the earliest practicable date on which the Board reasonably expects to have sufficient affirmative votes to obtain the Diamondback Stockholder Approval. Diamondback must at the request of Endeavor, to the extent permitted by law, adjourn the stockholders meeting to a date specified by Endeavor for the absence of a quorum or if Diamondback has not received proxies representing a sufficient number of shares of Diamondback common stock for the Diamondback Stockholder Approval; provided, that Diamondback will not be required to adjourn the stockholders meeting more than one time pursuant to this sentence, and no such adjournment pursuant to this sentence shall be required to be for a period exceeding ten business days.

Unless the Board has made an adverse recommendation change as described under the section entitled “—Change of Recommendation,” the Board will recommend that its stockholders adopt the Stock Issuance Proposal and use its reasonable best efforts to solicit from its stockholders proxies in favor of the Stock Issuance Proposal and take all other action necessary or advisable to obtain the Diamondback Stockholder Approval.

Diamondback’s obligation to hold the stockholder meeting will be affected by the commencement, public proposal, public disclosure or communication to Diamondback or any other person of any acquisition proposal or the occurrence of any adverse recommendation change by the Board.

Diamondback has agreed to use its reasonable best efforts to cause the shares of common stock to be issued as Common Stock Consideration to be approved for listing on Nasdaq, subject to official notice of issuance, prior to the First Merger Effective Time.

If requested in writing by Endeavor, which such request may be made by Endeavor no later than ten Business Days prior to the Closing Date, Diamondback must cooperate with Endeavor and its advisors to file a registration statement in accordance with the Securities Act to register the Common Stock Consideration, which registration statement, if Diamondback is then eligible to do so, must be an automatic shelf registration statement on Form S-3 and filed by Diamondback with the SEC no later than five business days after the Closing Date. Diamondback may satisfy its obligations with respect to the filing of any shelf registration statement by filing with the SEC a prospectus supplement under a “universal” or other shelf registration statement of Diamondback that also registers sales of securities for the account of Diamondback or other holders.

The Merger Agreement sets forth restrictions on Diamondback’s and Endeavor’s ability to engage with third parties regarding acquisition proposals.

Each of Diamondback and Endeavor have mutually agreed to:

Each of Diamondback and Endeavor has also agreed that it will not, and will cause each of its subsidiaries and other respective representatives not to, directly or indirectly:

The Merger Agreement also places additional restrictions on Diamondback with respect to acquisition proposals that it may receive. Specifically, Diamondback has agreed to promptly (and in any event within 24 hours of receipt) advise Endeavor in writing or orally in the event it receives:

Further, Diamondback has agreed to keep Endeavor reasonably informed on a timely basis of the status and details (including, within 24 hours after the occurrence of any material amendment, modification or development, discussion or negotiation) of any such acquisition proposal, request, inquiry, proposal or offer, including furnishing copies of any written correspondence or other materials provided to or Diamondback or its representatives, and copies of all draft documentation provided to or by Diamondback or its representatives.

An “acquisition proposal” means, with respect to Diamondback or Endeavor, as applicable, any proposal or offer from third party involving any direct or indirect acquisition or purchase or license, in one transaction or a series of transactions, and whether through any merger, reorganization, consolidation, tender offer, self-tender, exchange offer, stock acquisition, asset acquisition, binding share exchange, business combination, recapitalization, liquidation, dissolution, joint venture, licensing or similar transaction, or otherwise (except any transaction contemplated by the Merger Agreement) of:

Subject to certain exceptions described below, the Board has agreed to recommend that Diamondback stockholders vote “FOR” the Stock Issuance Proposal.

Under the Merger Agreement, an “adverse recommendation change” is deemed to have occurred if the Board (i) withdraws, modifies or qualifies its recommendation that stockholders approve the Stock Issuance, (ii) authorizes, recommends, adopts, approves, or declares the advisability (or publicly proposes to do the same) of, or agrees to submit to a vote of Diamondback stockholders, any acquisition proposal, (iii) publicly makes any recommendation in connection with any acquisition proposal that is a tender offer or exchange offer by a third party other than (A) an unequivocal recommendation against such offer pursuant to Rule 14d-2 of the Exchange Act, (B) a temporary “stop, look and listen” communication or (C) a communication to comply with certain applicable rules of the Exchange Act and regulations promulgated thereunder, (iv) fails to include the Board’s recommendation in the proxy statement, (v) publicly proposes or states its intention to take any of the foregoing actions, (vi) fails to publicly reaffirm its recommendation within ten business days of Endeavor’s written request to do so (or, if earlier, at least two business days prior to the stockholders meeting) following the public announcement of any acquisition proposal (or any material amendment, including any change to the price or form of consideration), provided that Endeavor may not make such a written request more than once with respect a specific acquisition proposal and each material modification thereof or (vii) commits or agrees to do any of the foregoing.

Prior to obtaining the Diamondback Stockholder Approval, the Board may only make an adverse recommendation change (i) in connection with an acquisition proposal that constitutes a “superior proposal” or (ii) in response to an “intervening event.” Both of these circumstances under which an adverse recommendation change may be made are described below.

The Board may make an adverse recommendation change in connection with a superior proposal if, prior to the receipt of the Diamondback Stockholder Approval, Diamondback:

Prior to the Board making an adverse recommendation change pursuant to the above:

If the Board determines that any proposal would cease to be a superior proposal by virtue of the revisions proposed by Endeavor, Diamondback must promptly (and in any event within 24 hours of such determination) so advise Endeavor and Endeavor and Diamondback will amend the Merger Agreement to reflect such offer made by Endeavor, and take all such actions as are necessary to give effect to the foregoing.

The Board has agreed to promptly (and in any event within two business days) reaffirm its original recommendation without qualification by press release if it determines that any proposal regarding an acquisition that is publicly announced or publicly disclosed does not constitute and would not reasonably be expected to lead to a superior proposal or if the Board determines that a proposed amendment by Endeavor to the terms of the Merger Agreement pursuant to the above would result in such a proposal no longer being a superior proposal.

A “superior proposal” means, any bona fide written acquisition proposal that did not result from a breach of Diamondback’s non-solicitation obligations under the Merger Agreement that the Board determines in good faith (after consultation with its advisors), taking into account all legal, financial, regulatory and other aspects of the proposal, including the terms of any financing or financing contingencies and the likely timing of closing, and the person making the proposal, is more favorable to Diamondback stockholders (solely in their capacity as such) from a financial point of view than the transactions contemplated by the Merger Agreement (including any binding adjustment to the terms and conditions proposed by Endeavor in writing in response to such proposal); provided, that, for purposes of the definition of “superior proposal,” references in the term “acquisition proposal” to “20% or more” are deemed to be references to “50% or more.”

The Board may make an adverse recommendation change if, prior to the receipt of the Diamondback Stockholder Approval, the Board determines that an intervening event has occurred.

Prior to the Board making an adverse recommendation change pursuant to the above, the Diamondback has agreed to take the following actions:

An “intervening event” means, a material event, fact, circumstance, development or circumstance that was not known or reasonably foreseeable to the Board prior to the execution of the Merger Agreement (or if known, the consequences of which were not known or reasonably foreseeable), which event, fact, circumstance, development or circumstance, or any material consequence thereof, becomes known to the Board, prior to the receipt of the Diamondback Stockholder Approval that does not relate to (i) an acquisition proposal, (ii) changes in the price of the common stock or debt securities issued by Endeavor, (iii) failure to meet internal or published financial or operating projections, estimates or expectations or (iv) any event, change, circumstance, development, condition, occurrence or effect with respect to Endeavor that does not amount to an Endeavor Material Adverse Effect.

In any case, if Diamondback provides a notice of a superior proposal or an intervening event to Endeavor on a date that is less than ten business days before the stockholders meeting, Diamondback has agreed to either proceed with or postpone the stockholders meeting as directed by Endeavor (acting reasonably) to a date determined by Endeavor that is not more than ten business days after the originally scheduled date of the special meeting. However, the stockholders meeting may not be postponed to a date which would prevent the Merger Effective Time from occurring on or prior to the Outside Date.

Diamondback and Endeavor each have agreed to use (and shall cause their respective subsidiaries to use) its reasonable best efforts to take, or cause to be taken, all actions, and to do, or cause to be done, and to assist and cooperate with the other party in doing, all things that are necessary, proper or advisable to consummate and make effective, in the most expeditious manner practicable, the transactions contemplated by the Merger Agreement. These include using their respective reasonable best efforts to:

However, Endeavor may not pay any fees or make any other concessions or waivers in connection with the above without first obtaining Diamondback’s written consent.

In addition, Diamondback has agreed to, and Endeavor has agreed (if requested by Diamondback), and will cause its subsidiaries, as necessary, to cooperate with Diamondback to, take any and all action necessary, to:

However, none of Diamondback or any of its subsidiaries is required to take any divestiture action that would reasonably be expected to have a regulatory material adverse effect. “Regulatory material adverse effect” means an effect on the financial condition, business, operations, revenue or EBITDA (as defined in the Merger Agreement) of Diamondback, Endeavor and their respective subsidiaries, taken as a whole, from and after the First Merger Effective Time that would be materially adverse to a hypothetical company that is 100% of the size of Endeavor and its subsidiaries, taken as a whole as of the date of the Merger Agreement. Endeavor may not offer, propose, agree to, or consent to effect any divestiture action without Diamondback’s prior written consent and, at the written request of Diamondback, has agreed to offer, propose, agree to, or consent to a divestiture action so long as such divestiture action is conditioned upon the Closing.

None of Endeavor nor Diamondback nor their respective subsidiaries and affiliates may enter into an agreement with a governmental authority to delay closing for any period beyond the statutory HSR Act waiting period without the written consent of the other party.

The parties have also agreed to not, and to cause their respective subsidiaries to not, consummate, enter into any agreement providing for, or announce, any investment, acquisition, divestiture or other business combination that would reasonably be expected to delay or prevent the consummation of the transactions contemplated by the Merger Agreement or increase the risk of not obtaining any action, consent, approval, registration, waiver, permit, authorization, order expiration or termination of waiting periods or other confirmations from any governmental entity that is a condition to the Closing, in each case, other than in an immaterial manner.

The obtaining of Financing, including the availability of the term loan commitments under the Bridge Commitment Letter and the takeout facility, is not a condition to Diamondback’s or the Merger Subs’ respective obligations under the Merger Agreement.

Until the Closing or the termination of the Merger Agreement, Diamondback has agreed to use its reasonable best efforts to take, or cause to be taken, all actions necessary, proper and advisable to obtain funds sufficient (when combined with other funds available to Diamondback) to satisfy its obligations under the Merger Agreement, including the payment of the cash consideration, fees and expenses payable under the Merger Agreement, and for any repayment or refinancing of Endeavor’s indebtedness contemplated by the Merger Agreement (collectively, the “Debt Financing Amount”).

In furtherance of the foregoing, Diamondback has agreed not to (i) amend the Commitment Letter, without Endeavor’s consent, if such amendment would reduce the amount of the Financing thereunder to an amount less than Diamondback would need, together with all other sources of funding available, to fund the Debt Financing Amount, or would modify the conditions thereto in a manner that would reasonably be expected to prevent or

materially impede or delay the consummation of the Merger or (ii) terminate the Commitment Letter to the extent doing so would reasonably be expected to prevent or materially impede or delay the consummation of the Merger.

Diamondback has agreed to (i) reasonably promptly upon request from Endeavor, provide Endeavor with updates about the preparation of the financing and (ii) promptly inform Endeavor after becoming aware of any circumstance or event which would reasonably be expected to prevent or materially impede or delay Diamondback’s ability to obtain funds sufficient to fund the Debt Financing Amounts.

Subject to certain limitations and other caveats, Endeavor has agreed, subject to certain customary exceptions, to (i) use reasonable best efforts to, (ii) cause its subsidiaries to use reasonable best efforts to and (iii) use reasonable best efforts to cause its and its subsidiaries’ respective directors, officers, employees, agents and advisors to use reasonable efforts to cooperate with Diamondback as necessary in connection with the arrangement of the Financing or any Permanent Financing as may be reasonably requested by Diamondback. Specifically, Endeavor and its subsidiaries must and must use reasonable best efforts to cause its and their respective representatives to:

Notwithstanding the foregoing, any breach of the foregoing obligations of Endeavor will not be asserted as the basis for (i) any condition precedent to consummate the Merger having not been satisfied or (ii) the termination of the Merger Agreement pursuant to the applicable provisions of the Merger Agreement, in each case, unless such breach is (A) a Willful and Material Breach that (B) causes the conditions in the Bridge Commitment Letter regarding delivery of certain financials of Endeavor (or substantially similar conditions in any replacement to such Bridge Commitment Letter described below) to not be satisfied and is (C) the primary cause of Diamondback being unable to obtain the proceeds of (x) the Financing at or prior to the First Merger Effective Time (such breach by the Endeavor, an “Endeavor Debt Breach”) or (y) any replacement to the Financing that is required for any reason other than Diamondback’s breach of any obligations related to the Financing or its failure to satisfy any of the conditions related thereto (it being understood that if, and only if, the Endeavor Debt Breach caused Diamondback’s breach or Diamondback’s failure to satisfy any of the

conditions related thereto, Diamondback will be deemed not to be in breach and will be deemed not to have failed to satisfy any of the conditions related thereto for the purposes of the foregoing clause (y).

Under the Merger Agreement, Diamondback has agreed that for a period of at least one year following the First Merger Effective Time, each individual who is employed by Endeavor immediately prior to the First Merger Effective Time and continues employment with the Surviving Company or its subsidiaries as of the Closing Date to be provided with the following:

Diamondback has agreed to also cause the Surviving Company and its subsidiaries to continue and honor its obligations under all employment, severance, change in control and other agreements (if any) between the Surviving Company or its subsidiaries, as applicable, and each individual who was employed by Endeavor or any of its subsidiaries immediately prior to the First Merger Effective Time.

For purposes of eligibility to participate, vesting and calculation of vacation or severance benefit entitlements (but not for any purposes with respect to defined benefit pension benefits or post-employment retiree welfare benefits) with respect to Diamondback’s benefit plans providing benefits to any Endeavor employee after the Closing Date, each Endeavor employee’s years of service with Endeavor or its subsidiaries (or a predecessor to the extent service with such predecessor was recognized by Endeavor or its subsidiaries, as applicable, as of the date of the Merger Agreement) prior to the First Merger Effective Time will be treated as service with Diamondback, subject to certain customary exceptions.

Endeavor has agreed to, effective as of the day prior to the First Merger Effective Time but contingent upon the Closing, cause to be approved resolutions terminating Endeavor LP’s 401(k) plan, unless Diamondback otherwise provides notice that such plan should not be terminated. As soon as administratively practicable following the Closing, each Endeavor employee will be eligible to participate in a tax qualified defined contribution plan established or designated by Diamondback (a “Diamondback 401(k) Plan”), subject to its terms and conditions. As soon as practicable after the Closing and to the extent not prohibited under applicable Law, Diamondback must also take commercially reasonable efforts to facilitate and effect an eligible rollover distribution (inclusive of any employee loans) for each Endeavor who elects to rollover his or her full account balance in Endeavor LP’s 401(k) plan to the Diamondback 401(k) Plan.

Prior to the Closing Date, Endeavor will submit for approval by the holders of the Endeavor Interests, in conformance with Section 280G of the Code and the regulations thereunder (the “280G Stockholder Vote”), any payments that could reasonably be expected to constitute a “parachute payment” pursuant to Section 280G of the Code (each, a “parachute payment”) on behalf of each “disqualified individual” (as defined in Section 280G of the Code and the regulations promulgated thereunder) and which are irrevocably waived by such individual. Prior to the distribution of the 280G stockholder vote materials, Endeavor will obtain an irrevocable waiver of the right to any parachute payment from each of the applicable “disqualified individuals” whose parachute payments would be subject to the 280G stockholder vote.

The parties have agreed that Diamondback will, and will cause the Surviving Company and its subsidiaries to, cause (i) any rights to indemnification, advancement of expenses or exculpation existing as of the Merger Agreement in favor of the directors, officers, members and managers of Endeavor, its managing member or any of the Surviving Company’s subsidiaries (each, an “indemnified party”) as provided in their respective organizational documents or indemnification agreements, in effect as of the date of the Merger Agreement, with respect to any matter occurring at or prior to the First Merger Effective Time (including the transactions

contemplated by the Merger Agreement) and (ii) any indemnification or other similar agreements of Endeavor or any of its subsidiaries in effect as of the date of the Merger Agreement to survive the Merger and continue in full force and effect for at least six years after the First Merger Effective Time. Additionally, during such period, Diamondback may not, nor will it permit the Surviving Company or any of its subsidiaries to, amend, repeal or otherwise modify such provisions for indemnification, advancement of expenses or exculpation in any manner that would materially and adversely affect the rights thereunder of any individual who at any time on or prior to the First Merger Effective Time was a director or officer of Endeavor, its managing member or any of the Surviving Company’s subsidiaries with respect to any matter occurring at or prior to the Merger Effective Time, unless such modification is required by law.

The parties have further agreed that, until the sixth year anniversary of the Merger Effective Time, Diamondback will cause the Surviving Company and its subsidiaries to the fullest extent permitted under applicable law (but subject to any limitation imposed from time to time under applicable law) indemnify each indemnified party against any and all losses, claims, damages, liabilities, fees, expenses, judgments or fines incurred in their capacity as officer, director, member, manager, employee or agent of Endeavor, its subsidiaries or its managing member in connection with any pending or threatened proceeding to the extent based on or arising out such indemnified party’s service at or prior to the First Merger Effective Time and pertaining to any and all matters pending, existing or occurring at or prior to the First Merger Effective Time, including with respect to the transactions contemplated by the Merger Agreement and (ii) advance reasonable and documented out-of-pocket costs and expenses incurred by any indemnified party in connection with matters for which such indemnified parties are eligible to be indemnified.

In addition the parties have agreed that Diamondback will cause to be put in place, and Diamondback must fully prepay prior to the First Merger Effective Time, “tail” insurance policies with a claims reporting or discovery period of at least six years from the Merger Effective Time from an insurance carrier with the same or better credit rating as Endeavor LP’s current insurance carrier with respect to directors’ and officers’ liability insurance in an amount and scope at least as favorable in the aggregate as Endeavor LP’s existing policies with respect to matters, acts or omissions existing or occurring at or prior to the Merger Effective Time, provided, however, that in no event shall the aggregate cost of such insurance exceed during the six-year tail period 300% of the current aggregate annual premium paid by Endeavor for such purpose and if the cost of such insurance coverage exceeds such amount, Diamondback must cause the Surviving Company, or its applicable subsidiary, to obtain a policy with the greatest coverage available for a cost not exceeding such amount.

Under the terms of the Merger Agreement, Diamondback and Endeavor made certain other covenants to and agreements with each other regarding other matters including, but not limited to:

The Merger Agreement contains a number of representations and warranties made by the parties thereto that are subject in some cases to exceptions and qualifications (including exceptions to the effect that there have not been, and would not reasonably be expected to be, a “Material Adverse Effect” (as defined below)).

The representations and warranties made by each party under the Merger Agreement relate to, among other things:

The Merger Agreement also contains additional representations and warranties of Diamondback and the Merger Subs relating to, among other things, the following:

For purposes of the Merger Agreement, “Material Adverse Effect” means, with respect to any person, any event, change, circumstance, development, condition, occurrence or effect that has, or would have, a material adverse effect on the business, condition (financial or otherwise), or results of operations of such person and its subsidiaries, taken as a whole, provided, however, that no event, change, circumstance, development, condition, occurrence or effect to the extent resulting from or arising out of the following will be deemed to be or to constitute a “Material Adverse Effect” or will be taken into account for purposes of determining whether a Material Adverse Effect has occurred or would occur: