HF Sinclair (DINO) S-4/ARegistration of securities issued in business combination transactions (amended)

As filed with the Securities and Exchange Commission on October 16, 2023

Registration No. 333-274655

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 1

to

FORM S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

HF SINCLAIR CORPORATION

(Exact name of Registrant as specified in its charter)

2828 N. Harwood, Suite 1300

Dallas, Texas 75201

(214) 871-3555

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Vaishali S. Bhatia

Executive Vice President, General Counsel and Secretary

HF Sinclair Corporation

2828 N. Harwood, Suite 1300

Dallas, Texas 75201

(214) 871-3555

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale of the securities to the public: As soon as practicable after this Registration Statement becomes effective and all other conditions to the proposed merger contemplated by the Agreement and Plan of Merger, dated August 15, 2023, described in the enclosed joint proxy statement/prospectus, have been satisfied or waived.

If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box. ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act. (Check one):

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

If applicable, place an X in the box to designate the appropriate rule provision relied upon in conducting this transaction:

The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act or until this Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this document is not complete and may be changed. HF Sinclair Corporation may not sell the securities offered by this document until the registration statement filed with the U.S. Securities and Exchange Commission, of which this document is a part, is declared effective. This document shall not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any jurisdiction where such offer, solicitation or sale is not permitted.

PRELIMINARY— SUBJECT TO COMPLETION DATED OCTOBER 16, 2023

MERGER PROPOSAL—YOUR VOTE IS VERY IMPORTANT

To the Stockholders of HF Sinclair Corporation and the Unitholders of Holly Energy Partners, L.P.:

On August 15, 2023, HF Sinclair Corporation (“HF Sinclair”) and Holly Energy Partners, L.P. (“HEP”) entered into an Agreement and Plan of Merger (as the same may be amended or supplemented from time to time, the “Merger Agreement”) with Holly Logistic Services, L.L.C. (the “General Partner”), the general partner of HEP Logistics Holdings, L.P. (“HLH”); HLH, the general partner of HEP; Navajo Pipeline Co., L.P., an indirect wholly owned subsidiary of HF Sinclair (“HoldCo”); and Holly Apple Holdings LLC, a wholly owned subsidiary of HoldCo (“Merger Sub”); pursuant to which Merger Sub will merge with and into HEP (the “Merger”), with HEP surviving as an indirect wholly owned subsidiary of HF Sinclair.

Under the terms of the Merger Agreement, if the Merger is completed, at the effective time of the Merger (the “Effective Time”), each outstanding common unit representing a limited partner interest in HEP (each, a “HEP Common Unit”) other than the HEP Common Units already owned by HF Sinclair and its subsidiaries, including HoldCo, will be converted into the right to receive (i) 0.315 (the “Exchange Ratio”) shares of common stock, par value $0.01 per share, of HF Sinclair (the “HF Sinclair Common Stock”), with cash paid in lieu of the issuance of fractional shares, if any, and (ii) $4.00 in cash, without interest (the “Cash Consideration” and, together with the shares of HF Sinclair Common Stock to be issued in the Merger, the “Merger Consideration”). Existing stockholders of HF Sinclair (“HF Sinclair Stockholders”) will continue to own their existing HF Sinclair Common Stock. Upon the closing of the Merger, former holders of HEP Common Units (“HEP Unitholders”) and existing HF Sinclair Stockholders will own approximately 10% and 90%, respectively, of the HF Sinclair Common Stock.

In connection with the Merger, (i) HLH’s non-economic general partner interest in HEP, (ii) HLH’s special general partner interest in HEP (the “Special General Partner Interest”), and (iii) the HEP Common Units owned by HF Sinclair and its subsidiaries, including HoldCo, will not be cancelled, will not be converted into the Merger Consideration and will remain outstanding following the Merger as a non-economic general partner interest in HEP, a Special General Partner Interest in HEP and as HEP Common Units, respectively.

In connection with the Merger, HF Sinclair will hold a special meeting of its stockholders (as the same may be adjourned or postponed, the “HF Sinclair Special Meeting”) and HEP will hold a special meeting of its unitholders (as the same may be adjourned or postponed, the “HEP Special Meeting”).

At the HF Sinclair Special Meeting, the HF Sinclair Stockholders will be asked to consider and vote on proposals to (i) approve the issuance of shares of HF Sinclair Common Stock to HEP Unitholders pursuant to the Merger Agreement (the “HF Sinclair Stock Issuance Proposal”) and (ii) approve the adjournment of the HF Sinclair Special Meeting to a later date or dates, if necessary or appropriate, to solicit additional proxies in the event there are not sufficient votes at the time of the HF Sinclair Special Meeting to approve the HF Sinclair Stock Issuance Proposal (the “HF Sinclair Adjournment Proposal”). The approval by the HF Sinclair Stockholders of the HF Sinclair Stock Issuance Proposal is required by New York Stock Exchange (“NYSE”) rules relating to issuances of securities to certain related parties.

The conflicts committee (the “HF Sinclair Conflicts Committee”) of the board of directors of HF Sinclair (the “HF Sinclair Board”) and the HF Sinclair Board have unanimously approved the Merger Agreement and recommend that HF Sinclair Stockholders vote “FOR” the HF Sinclair Stock Issuance Proposal. The HF Sinclair Board recommends that HF Sinclair Stockholders vote

“FOR” the HF Sinclair Adjournment Proposal. The HF Sinclair Stockholders should be aware that certain of the directors, executive officers and other affiliates of HF Sinclair may have interests in the Merger that are different from, or in addition to, the interests they may have as a HF Sinclair Stockholder. See “Special Factors—Interests of Certain Persons in the Merger.”

At the HEP Special Meeting, the HEP Unitholders will be asked to consider and vote on proposals to (i) approve the Merger Agreement and the transactions contemplated thereby (the “Merger Proposal”) and (ii) approve the adjournment of the HEP Special Meeting to a later date or dates, if necessary or appropriate, to solicit additional proxies in the event there are not sufficient votes at the time of the HEP Special Meeting to approve the Merger Proposal (the “HEP Adjournment Proposal”). Pursuant to the Merger Agreement, HF Sinclair has agreed that it will vote, or cause to be voted, all HEP Common Units then owned beneficially or of record by HF Sinclair or any of its subsidiaries in favor of the Merger Proposal. HF Sinclair currently holds approximately 47% of the issued and outstanding HEP Common Units through its subsidiaries, along with the non-economic general partner interest and the Special General Partner Interest.

The conflicts committee of the board of directors of the General Partner (the “HEP Conflicts Committee”) as well as the board of directors of the General Partner have unanimously and in good faith approved the Merger Agreement and recommend that HEP Unitholders vote “FOR” the Merger Proposal. The board of directors of the General Partner also recommends that HEP Unitholders vote “FOR” the HEP Adjournment Proposal. The HEP Unitholders should be aware that certain of the directors, executive officers and other affiliates of the General Partner and certain members of the HEP Conflicts Committee may have interests in the Merger that are different from, or in addition to, the interests they may have as a HEP Unitholder. See “Special Factors—Interests of Certain Persons in the Merger.”

Although the number of shares of HF Sinclair Common Stock that HEP Unitholders will receive in exchange for their HEP Common Units is fixed, the market value of the Merger Consideration will fluctuate with the market price of HF Sinclair Common Stock and will not be known at the time HEP Unitholders vote on the Merger Proposal or at the time HF Sinclair Stockholders vote on the HF Sinclair Stock Issuance Proposal. Based on the closing price of HF Sinclair Common Stock on the NYSE on August 15, 2023, the last trading day before the public announcement of the parties entering into the Merger Agreement, the Exchange Ratio represented approximately $17.71 in value for each HEP Common Unit for total Merger Consideration of $21.71 for each HEP Common Unit. Based on the closing price of HF Sinclair Common Stock on the NYSE on     , 2023, the most recent practicable day before the printing of the accompanying joint proxy statement/prospectus, the Exchange Ratio represented approximately $     in value for each HEP Common Unit for a total Merger Consideration of $     for each HEP Common Unit. We urge you to obtain current market quotations for HF Sinclair Common Stock (trading symbol “DINO”) and HEP Common Units (trading symbol “HEP”).

We cannot complete the Merger unless the HF Sinclair Stockholders approve the HF Sinclair Stock Issuance Proposal and the HEP Unitholders approve the Merger Proposal. Accordingly, your vote is very important regardless of the number of shares of HF Sinclair Common Stock or HEP Common Units you own. Voting instructions are set forth inside this joint proxy statement/prospectus.

The obligations of HF Sinclair and HEP to complete the Merger are subject to the satisfaction or waiver of a number of conditions set forth in the Merger Agreement, a copy of which is attached as Annex A to the accompanying joint proxy statement/prospectus. The accompanying joint proxy statement/prospectus describes the HF Sinclair Special Meeting and the proposals to be considered thereat, the HEP Special Meeting and the proposals to be considered thereat, the Merger and the documents and agreements related to the Merger. It also contains or incorporates by reference information about HF Sinclair and HEP and certain related agreements and matters. Please carefully read the entire accompanying joint proxy statement/prospectus, including “Risk Factors” beginning on page 22, for a discussion of the risks relating to the proposed Merger. You also can obtain information about HF Sinclair and HEP from documents that each has filed with the U.S. Securities and Exchange Commission. Please see “Where You Can Find More Information” beginning on page 184 of the accompanying joint proxy statement/prospectus for how you may obtain such information.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued in connection with the Merger described in the accompanying joint proxy statement/prospectus or determined that the accompanying joint proxy statement/prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

The accompanying document is dated     , 2023 and is first being mailed to the HF Sinclair Stockholders and HEP Unitholders on or about     , 2023.

Dallas, Texas

   , 2023

HF Sinclair Corporation

2828 N. Harwood, Suite 1300

Dallas, Texas 75201

NOTICE OF VIRTUAL SPECIAL MEETING OF STOCKHOLDERS

To the Stockholders of HF Sinclair Corporation:

You are cordially invited to attend the virtual special meeting (as the same may be adjourned or postponed, the “HF Sinclair Special Meeting”) of stockholders of HF Sinclair Corporation (“HF Sinclair”), which will be held exclusively via a live audio webcast on     , 2023 at 9:30 a.m., Central Time, at https://www.virtualshareholdermeeting.com/DINO2023SM, for the following purposes:

The HF Sinclair Special Meeting will be held via a live audio webcast in a virtual meeting format at https://www.virtualshareholdermeeting.com/DINO2023SM. Holders of HF Sinclair Common Stock (the “HF Sinclair Stockholders”) will not be able to attend the HF Sinclair Special Meeting physically in-person. The accompanying joint proxy statement/prospectus includes instructions on how to access the virtual HF Sinclair Special Meeting and how to participate and vote from home or any remote location with Internet connectivity. You or your proxy holder will be able to virtually attend and vote at the virtual HF Sinclair Special Meeting by visiting https://www.virtualshareholdermeeting.com/DINO2023SM and using the 16-digit control number on your proxy card.

Assuming a quorum is present, approval of the HF Sinclair Stock Issuance Proposal requires approval by a majority of the votes cast by HF Sinclair Stockholders entitled to vote on such proposal. The HF Sinclair Adjournment Proposal requires the approval by a majority in interest of the stockholders entitled to vote at the HF Sinclair Special Meeting, present in person or represented by proxy. Virtual attendance at the special meeting will constitute presence in person for the purpose of determining the presence of a quorum for the transaction of business at the HF Sinclair Special Meeting.

The parties to the Merger Agreement cannot complete the Merger unless the HF Sinclair Stock Issuance Proposal is approved at the HF Sinclair Special Meeting. Accordingly, your vote is very important regardless of the number of shares of HF Sinclair Common Stock you own.

The conflicts committee (the “HF Sinclair Conflicts Committee”) of the board of directors of HF Sinclair (the “HF Sinclair Board”) has unanimously (i) determined that the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, are advisable and in the best interests of HF Sinclair and the HF Sinclair Stockholders, (ii) approved the Merger Agreement and the Transactions, including the Merger and the

HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, (iii) recommended that the HF Sinclair Board approve the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, and (iv) resolved and recommended that the HF Sinclair Board resolve, to (a) direct that the HF Sinclair Stock Issuance be submitted to a vote of the HF Sinclair Stockholders for approval at the HF Sinclair Special Meeting and (b) recommend approval of the HF Sinclair Stock Issuance by the HF Sinclair Stockholders at the HF Sinclair Special Meeting.

The HF Sinclair Board (acting, in part, based upon the recommendation of the HF Sinclair Conflicts Committee) has unanimously (i) determined that the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, are advisable and in the best interests of HF Sinclair and the HF Sinclair Stockholders, (ii) approved the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, (iii) directed that the HF Sinclair Stock Issuance be submitted to a vote of the HF Sinclair Stockholders for approval at the HF Sinclair Special Meeting and (iv) resolved to recommend approval of the HF Sinclair Stock Issuance by the HF Sinclair Stockholders at the HF Sinclair Special Meeting.

The HF Sinclair Board and HF Sinclair Conflicts Committee unanimously recommend that the HF Sinclair Stockholders vote “FOR” the HF Sinclair Stock Issuance Proposal. The HF Sinclair Board unanimously recommends that the HF Sinclair Stockholders vote “FOR” the HF Sinclair Adjournment Proposal. For more information regarding the recommendations of the HF Sinclair Board, see “Special Factors—Recommendations of the HF Sinclair Conflicts Committee and the HF Sinclair Board and their Reasons for the Merger.”

The HF Sinclair Stockholders should be aware that certain of the directors, executive officers and other affiliates of HF Sinclair may have interests in the Merger that are different from, or in addition to, the interests they may have as a HF Sinclair Stockholder. See “Special Factors—Interests of Certain Persons in the Merger.”

Only the HF Sinclair Stockholders of record at the close of business on     , 2023 are entitled to notice of and to vote at the HF Sinclair Special Meeting. References to the HF Sinclair Special Meeting in this joint proxy statement/prospectus are to such virtual special meeting as the same may be adjourned or postponed from time to time.

TO PARTICIPATE IN THE VIRTUAL SPECIAL MEETING, A HF SINCLAIR STOCKHOLDER OF RECORD WILL NEED THE 16-DIGIT CONTROL NUMBER INCLUDED ON SUCH HOLDER’S PROXY CARD OR INSTRUCTIONS THAT ACCOMPANIED SUCH HOLDER’S PROXY MATERIALS. THE LIVE AUDIO WEBCAST OF THE HF SINCLAIR SPECIAL MEETING WILL BEGIN PROMPTLY ON     , 2023 AT 9:30 A.M., CENTRAL TIME, AT HTTPS://WWW.VIRTUALSHAREHOLDERMEETING.COM/DINO2023SM. THE HF SINCLAIR STOCKHOLDERS ARE ENCOURAGED TO ACCESS THE HF SINCLAIR SPECIAL MEETING PRIOR TO THE START TIME. ONLINE ACCESS AND CHECK-IN WILL BEGIN AT 9:15 A.M., CENTRAL TIME. TECHNICAL SUPPORT WILL BE AVAILABLE ON THE VIRTUAL MEETING PLATFORM BEGINNING AT 9:15 A.M., CENTRAL TIME ON     , 2023 THROUGH THE CONCLUSION OF THE HF SINCLAIR SPECIAL MEETING. IF YOU ENCOUNTER ANY DIFFICULTIES ACCESSING THE VIRTUAL MEETING DURING THE CHECK-IN OR MEETING TIME, PLEASE DIAL THE TECHNICAL ASSISTANCE NUMBERS SHOWN ON THE VIRTUAL MEETING PLATFORM. YOUR VOTE IS IMPORTANT. WHETHER OR NOT YOU EXPECT TO VIRTUALLY ATTEND THE HF SINCLAIR SPECIAL MEETING, PLEASE SUBMIT YOUR PROXY IN ONE OF THE FOLLOWING WAYS:

The enclosed joint proxy statement/prospectus provides a detailed description of the HF Sinclair Stock Issuance Proposal and the Merger Agreement. You are urged to read this joint proxy statement/prospectus, including any documents incorporated by reference, and the Annexes carefully and in their entirety. This joint proxy statement/prospectus and the Notice of Virtual Special Meeting of Stockholders relating to the Merger and the HF Sinclair Stock Issuance Proposal will be available at https://www.proxyvote.com. If you have any questions concerning the Merger or the HF Sinclair Stock Issuance Proposal or this joint proxy statement/prospectus, would like additional copies or need help voting your shares of HF Sinclair Common Stock, please contact HF Sinclair’s proxy solicitor:

MacKenzie Partners, Inc.

1407 Broadway

New York, New York 10018

Call (212) 929-5500 / Toll-Free: (800) 322-2885

Email: proxy@mackenziepartners.com

Sincerely,

Vaishali S. Bhatia

Executive Vice President, General Counsel and Secretary

HF Sinclair Corporation

Dallas, Texas

   , 2023

Holly Energy Partners, L.P.

2828 N. Harwood, Suite 1300

Dallas, Texas 75201

NOTICE OF VIRTUAL SPECIAL MEETING OF UNITHOLDERS

To the Unitholders of Holly Energy Partners, L.P.:

You are cordially invited to attend the virtual special meeting (as the same may be adjourned or postponed, the “HEP Special Meeting”) of unitholders of Holly Energy Partners, L.P. (“HEP”) which will be held exclusively via a live audio webcast on     , 2023 at 8:30 a.m., Central Time, at https://www.virtualshareholdermeeting.com/HEP2023SM, for the following purposes:

The HEP Special Meeting will be held via a live audio webcast in a virtual meeting format at https://www.virtualshareholdermeeting.com/HEP2023SM. Holders of common units representing limited partner interests in HEP (the “HEP Common Units” and such holders, the “HEP Unitholders”) will not be able to attend the HEP Special Meeting in-person. The accompanying joint proxy statement/prospectus includes instructions on how to access the virtual HEP Special Meeting and how to participate and vote from home or any remote location with Internet connectivity. You or your proxy holder will be able to virtually attend and vote at the virtual HEP Special Meeting by visiting https://www.virtualshareholdermeeting.com/HEP2023SM and using the 16-digit control number on your proxy card.

Upon the terms and subject to the conditions set forth in the Merger Agreement, upon consummation of the Merger (as defined below), Merger Sub will merge with and into HEP, with HEP surviving as an indirect wholly owned subsidiary of HF Sinclair (the “Merger”). Approval of the Merger Proposal requires the affirmative vote of holders of a majority of the outstanding HEP Common Units. In the absence of a quorum, approval of the HEP Adjournment Proposal requires the affirmative vote of HEP Unitholders representing a majority of the outstanding HEP Common Units entitled to vote and represented in person or by proxy at the HEP Special Meeting. If a quorum is present, approval of the HEP Adjournment proposal requires the affirmative vote of holders of a majority of the outstanding HEP Common Units. Virtual attendance at the special meeting will constitute presence in person for the purpose of determining the presence of a quorum for the transaction of business at the HF Sinclair Special Meeting.

Pursuant to the Merger Agreement, HF Sinclair has agreed that it will vote, or cause to be voted, all HEP Common Units then owned beneficially or of record by HF Sinclair or any of its subsidiaries in favor of the

Merger Proposal. HF Sinclair currently holds approximately 47% of the issued and outstanding HEP Common Units through its subsidiaries, along with the non-economic general partner interest and the special general partner interest.

The parties to the Merger Agreement cannot complete the Merger unless holders of a majority of the outstanding HEP Common Units approve the Merger Proposal. Accordingly, your vote is very important regardless of the number of HEP Common Units you own.

The conflicts committee (the “HEP Conflicts Committee”) of the board of directors of the General Partner (the “GP Board”) has unanimously and in good faith (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are in the best interests of HEP, including the HEP Unitholders other than HF Sinclair, HoldCo, HLH, the General Partner and their respective Affiliates, including officers and directors of such entities and their Affiliates (the “HEP Unaffiliated Unitholders”), (ii) approved the Merger Agreement and the transactions contemplated thereby, including the Merger (the foregoing constituting “Special Approval” for all purposes of the Second Amended and Restated Agreement of Limited Partnership of HEP, dated as of October 31, 2017, as may be further amended, modified or supplemented from time to time, including Section 7.9(a) thereof) on the terms and subject to the conditions set forth in the Merger Agreement, (iii) recommended that the GP Board approve the Merger Agreement and the transactions contemplated thereby, including the Merger, on the terms and subject to the conditions set forth in the Merger Agreement, and (iv) resolved and recommended that the GP Board resolve to (a) direct that the Merger Agreement and the Merger be submitted to a vote of the HEP Unitholders for approval and (b) recommend approval of the Merger Agreement and the Merger by the HEP Unitholders at the HEP Special Meeting.

The GP Board (acting, in part, based upon the recommendation of the HEP Conflicts Committee) has unanimously and in good faith (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are in the best interests of HEP, including the HEP Unaffiliated Unitholders, (ii) approved the Merger Agreement and the transactions contemplated thereby, including the Merger, on the terms and subject to the conditions set forth in the Merger Agreement, (iii) directed that the Merger Agreement and the Merger be submitted to a vote of the HEP Unitholders for approval and (iv) resolved to recommend approval of the Merger Agreement and the Merger by the HEP Unitholders at the HEP Special Meeting.

Each of the HEP Conflicts Committee and the GP Board unanimously recommends that the HEP Unitholders vote “FOR” the Merger Proposal. The GP Board also recommends that the HEP Unitholders vote “FOR” the HEP Adjournment Proposal. For more information regarding the recommendations of the HEP Conflicts Committee and the GP Board, see “Special Factors—Recommendations of the HEP Conflicts Committee and the GP Board and the Reasons for their Recommendations.”

The HEP Unitholders should be aware that certain of the directors, executive officers and other affiliates of the General Partner and certain members of the HEP Conflicts Committee may have interests in the Merger that are different from, or in addition to, the interests they may have as a HEP Unitholder. See “Special Factors—Interests of Certain Persons in the Merger.”

Only the HEP Unitholders of record at the close of business on     , 2023 are entitled to notice of and to vote at the HEP Special Meeting. References to the HEP Special Meeting in this joint proxy statement/prospectus are to such virtual special meeting as the same may be adjourned or postponed from time to time.

TO PARTICIPATE IN THE VIRTUAL SPECIAL MEETING, A HEP UNITHOLDER OF RECORD WILL NEED THE 16-DIGIT CONTROL NUMBER INCLUDED ON SUCH HOLDER’S PROXY CARD OR INSTRUCTIONS THAT ACCOMPANIED SUCH HOLDER’S PROXY MATERIALS. THE LIVE AUDIO WEBCAST OF THE HEP SPECIAL MEETING WILL BEGIN PROMPTLY ON     , 2023 AT 8:30 A.M., CENTRAL TIME, AT HTTPS://WWW.VIRTUALSHAREHOLDERMEETING.COM/HEP2023SM. THE HEP UNITHOLDERS ARE ENCOURAGED TO ACCESS THE HEP SPECIAL MEETING PRIOR TO THE START TIME. ONLINE ACCESS AND CHECK-IN WILL BEGIN AT 8:15 A.M., CENTRAL TIME. TECHNICAL SUPPORT WILL BE AVAILABLE ON THE VIRTUAL MEETING PLATFORM BEGINNING AT 8:15 A.M., CENTRAL TIME ON     , 2023 THROUGH

THE CONCLUSION OF THE HEP SPECIAL MEETING. IF YOU ENCOUNTER ANY DIFFICULTIES ACCESSING THE VIRTUAL MEETING DURING THE CHECK-IN OR MEETING TIME, PLEASE DIAL THE TECHNICAL ASSISTANCE NUMBERS SHOWN ON THE VIRTUAL MEETING PLATFORM. YOUR VOTE IS IMPORTANT. WHETHER OR NOT YOU EXPECT TO VIRTUALLY ATTEND THE HEP SPECIAL MEETING, PLEASE SUBMIT YOUR PROXY IN ONE OF THE FOLLOWING WAYS:

The enclosed joint proxy statement/prospectus provides a detailed description of the Merger and the Merger Agreement. You are urged to read this joint proxy statement/prospectus, including any documents incorporated by reference, and the Annexes carefully and in their entirety. This joint proxy statement/prospectus and the Notice of Virtual Special Meeting of Unitholders relating to the Merger will be available at https://www.proxyvote.com. If you have any questions concerning the Merger or this joint proxy statement/prospectus, would like additional copies or need help voting your HEP Common Units, please contact HEP’s proxy solicitor:

MacKenzie Partners, Inc.

1407 Broadway

New York, New York 10018

Call (212) 929-5500 / Toll-Free: (800) 322-2885

Email: proxy@mackenziepartners.com

Sincerely,

Vaishali S. Bhatia

Executive Vice President, General Counsel and Secretary

Holly Logistic Services, L.L.C.

the general partner of HEP Logistics Holdings, L.P.,

which is the general partner of Holly Energy Partners, L.P.

IMPORTANT NOTE ABOUT THIS JOINT PROXY STATEMENT/PROSPECTUS

This joint proxy statement/prospectus, which forms part of a registration statement on Form S-4 filed with the SEC by HF Sinclair, constitutes a prospectus of HF Sinclair under Section 5 of the Securities Act with respect to the HF Sinclair Common Stock to be issued in connection with the Merger Agreement. This document also constitutes a proxy statement of HF Sinclair and of HEP under Section 14(a) of the Exchange Act and a notice of meeting with respect to the HF Sinclair Special Meeting and the HEP Special Meeting. This joint proxy statement/prospectus does not constitute an offer to exchange or sell, or a solicitation of offers to exchange or purchase or the solicitation of a proxy in any jurisdiction in which or from any person to whom it is unlawful to make any such offer or solicitation in such jurisdiction.

As permitted under the rules of the SEC, this joint proxy statement/prospectus incorporates by reference important business and financial information about HF Sinclair and HEP from other documents filed with the SEC that are not included in or delivered with this joint proxy statement/prospectus. See “Where You Can Find More Information” beginning on page 184. You can obtain any of the documents incorporated by reference into this document from HF Sinclair or HEP, as the case may be, or from the SEC’s website at http://www.sec.gov. This information is also available to you without charge upon your request in writing or by telephone from HF Sinclair or HEP at the following addresses and telephone numbers:

Please note that copies of the documents provided to you will not include exhibits, unless the exhibits are specifically incorporated by reference into the documents or this joint proxy statement/prospectus.

You may obtain certain of these documents at HF Sinclair’s website at http://www.hfsinclair.com and HEP’s website at http://www.hollyenergy.com. Information contained on HF Sinclair’s and HEP’s websites is expressly not incorporated by reference into this joint proxy statement/prospectus.

In order to receive timely delivery of requested documents in advance of the HF Sinclair Special Meeting and HEP Special Meeting, your request should be received no later than five business days before the date of each respective Special Meeting, which means your request should be received no later than     , 2023. If you request any documents, HF Sinclair or HEP, as applicable, will mail them to you by first class mail, or another equally prompt means, after receipt of your request.

In “Questions and Answers” and in the “Summary Term Sheet” below, selected information from this joint proxy statement/prospectus is highlighted, but not all of the information that may be important to you is included. To better understand the Merger Agreement, the Merger and the HF Sinclair Stock Issuance, and for a more complete description of its legal terms, you should carefully read this entire joint proxy statement/prospectus, including the section entitled “Risk Factors” beginning on page 22 of this joint proxy statement/prospectus and the Merger Agreement, a copy of which is attached hereto as Annex A, as well as the documents that are incorporated by reference into this joint proxy statement/prospectus. See “Where You Can Find More Information.”

HF Sinclair and HEP have not authorized anyone to give any information or make any representation about the Merger, HF Sinclair or HEP that is different from, or in addition to, that contained in this joint proxy statement/prospectus or in any of the materials that have been incorporated by reference into this joint proxy statement/prospectus. Therefore, if anyone distributes this type of information, you should not rely on it. If you are in a jurisdiction where offers to exchange or sell, or solicitations of offers to exchange or purchase, the securities offered by this joint proxy statement/prospectus or the solicitation of proxies are unlawful, or you are a person to whom it is unlawful to direct these types of activities, then the offer presented in this joint proxy statement/

prospectus does not extend to you. The information contained in this joint proxy statement/prospectus speaks only as of the date of this joint proxy statement/prospectus, or in the case of information in a document incorporated by reference, as of the date of such document, unless the information specifically indicates that another date applies. All information in this document concerning HF Sinclair has been furnished by HF Sinclair. All information in this document concerning HEP has been furnished by HEP.

JOINT PROXY STATEMENT/PROSPECTUS

TABLE OF CONTENTS

i

CERTAIN DEFINED TERMS

ii

iii

iv

1

2

3

4

5

6

7

8

QUESTIONS AND ANSWERS

Important Information and Risks. The following are brief answers to some questions that you may have regarding the proposed Merger, the HF Sinclair Special Meeting and the HEP Special Meeting. You should read and consider carefully the remainder of this joint proxy statement/prospectus, including the Risk Factors beginning on page 22 and the attached Annexes, because the information in this section does not provide all of the information that might be important to you. Additional important information and descriptions of risk factors are also contained in the documents incorporated by reference in this joint proxy statement/prospectus. See “Where You Can Find More Information” beginning on page 184.

You are receiving this joint proxy statement/prospectus because HF Sinclair and HEP have entered into the Merger Agreement, pursuant to which, on the terms and subject to the fulfillment or, to the extent permissible under applicable law, waiver of the conditions included in the Merger Agreement, Merger Sub will merge with and into HEP; the separate existence of Merger Sub will cease and HEP will continue as the Surviving Entity in the Merger as an indirect wholly owned subsidiary of HF Sinclair. The Merger Agreement governs the terms of the Merger of Merger Sub and HEP and is attached to this joint proxy statement/prospectus as Annex A.

In order to complete the Merger, among other things, HF Sinclair Stockholders must approve the issuance of HF Sinclair Common Stock (the “HF Sinclair Stock Issuance”) in connection with the Merger under the rules of the NYSE related to related party transactions (the “HF Sinclair Stock Issuance Proposal”) and HEP Unitholders must approve the Merger Agreement and the Merger in accordance with Delaware law and the HEP Partnership Agreement (the “Merger Proposal”).

This joint proxy statement/prospectus serves as both the proxy statement through which HF Sinclair and HEP will solicit proxies to obtain the necessary stockholder and unitholder approvals for the Merger and the prospectus forming part of the Registration Statement on Form S-4 by which HF Sinclair will issue shares of HF Sinclair Common Stock as consideration in the Merger.

This joint proxy statement/prospectus, which you should carefully read in its entirety, contains important information about the HF Sinclair Special Meeting and HEP Special Meeting, the Merger and other matters.

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The Merger Agreement is attached to this joint proxy statement/prospectus as Annex A. For a more complete discussion of the proposed Merger, its effects and the other Transactions, please see “The Merger Agreement.”

Because HF Sinclair will issue a fixed number of shares of HF Sinclair Common Stock in exchange for each HEP Public Common Unit, the value of the Merger Consideration that HEP Public Unitholders will receive in the Merger will depend on the market price of shares of HF Sinclair Common Stock at the Effective Time. The market price of shares of HF Sinclair Common Stock that HEP Public Unitholders receive at the Effective Time could be greater than, less than or the same as the market price of shares of HF Sinclair Common Stock on the date of this joint proxy statement/prospectus or at the time of the HEP Special Meeting. Accordingly, you should obtain current market quotations for HF Sinclair Common Stock and HEP Common Units before deciding how to vote with respect to the Merger Proposal or the HF Sinclair Stock Issuance Proposal, as applicable. HF Sinclair Common Stock is traded on the NYSE under the trading symbol “DINO.” HEP Common Units are traded on the NYSE under the trading symbol “HEP.”

For more information regarding the Merger Consideration to be received by HEP Public Unitholders if the Merger is completed, please see “The Merger Agreement.”

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The record date for the HEP Special Meeting is     , 2023 (the “HEP record date”). Only the HEP Unitholders of record as of the close of business on the HEP record date are entitled to notice of, and to vote at, the HEP Special Meeting.

The HEP record date for the HEP Special Meeting is earlier than the date of the HEP Special Meeting and earlier than the date that the Merger is expected to be completed. If you sell or otherwise transfer your HEP Public Common Units after the HEP record date but before the date of the HEP Special Meeting, you will retain your right to vote at the HEP Special Meeting. However, you will not have the right to receive the Merger Consideration to be received by the HEP Public Unitholders in the Merger. In order to receive the Merger Consideration, you must hold your HEP Public Common Units as of the Effective Time.

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The holders of a majority of the outstanding HEP Common Units entitled to vote at the HEP Special Meeting (including outstanding HEP Common Units directly or indirectly owned by HF Sinclair) represented in person or by proxy at the HEP Special Meeting will constitute a quorum and will permit HEP to conduct the proposed business at the HEP Special Meeting. Virtual attendance at the HEP Special Meeting will constitute presence in person for the purpose of determining the presence of a quorum. Proxies received but marked as abstentions will be counted as HEP Common Units that are present and entitled to vote for purposes of determining the presence of a quorum. Broker non-votes (if any) will not be considered present or represented at the HEP Special Meeting for purposes of determining the presence of a quorum.

All of the directors and executive officers of HF Sinclair beneficially owned, in the aggregate, less than 1% of the outstanding shares of HF Sinclair Common Stock as of October 12, 2023.

The approval of the HF Sinclair Stock Issuance Proposal is a condition to the obligations of HF Sinclair and HEP to complete the Merger. The HF Sinclair Stockholder Approval is required by NYSE rules relating to issuances of securities to certain related parties. The approval of the HF Sinclair Adjournment Proposal is not a condition to the obligations of HF Sinclair or HEP to complete the Merger.

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HF Sinclair and its subsidiaries beneficially owned, in the aggregate, approximately 47.2% of the outstanding HEP Common Units as of October 12, 2023. Pursuant to the terms of the Merger Agreement, HF Sinclair and its subsidiaries have agreed to vote their shares in favor of the Merger Proposal and the HEP Adjournment Proposal.

All of the directors and executive officers of the General Partner beneficially owned, in the aggregate, less than 1% of the outstanding HEP Common Units as of October 12, 2023.

Approval of the Merger Proposal is a condition to the obligations of HF Sinclair and HEP to complete the Merger. The approval of the HEP Adjournment Proposal is not a condition to the obligations of HF Sinclair or HEP to complete the Merger.

The deadline for submitting your proxy by mail, telephone or electronically through the Internet website listed on your proxy card is 10:59 p.m., Central Time, on the date prior to the HF Sinclair Special Meeting.

If you virtually attend the HF Sinclair Special Meeting and want to vote during the virtual meeting, you will be able to do so using the control number included on your proxy card or instructions that accompanied your proxy materials. The control number located on your proxy card is designed to verify your identity and allow you to vote your shares of HF Sinclair Common Stock and to confirm that your voting instructions have been properly recorded when voting electronically over the Internet or by telephone.

The deadline for submitting your proxy by mail, telephone or electronically through the Internet website listed on your proxy card is 10:59 p.m., Central Time, on the date prior to the HEP Special Meeting.

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If you virtually attend the HEP Special Meeting and want to vote during the virtual meeting, you will be able to do so using the control number included on your proxy card or instructions that accompanied your proxy materials. The control number located on your proxy card is designed to verify your identity and allow you to vote your HEP Common Units and to confirm that your voting instructions have been properly recorded when voting electronically over the Internet or by telephone.

You will need the 16-digit control number found on your proxy card or voting instruction form in order to participate in the HF Sinclair Special Meeting (including voting your shares of HF Sinclair Common Stock). As the HF Sinclair Special Meeting is virtual, there will be no physical meeting location and HF Sinclair Stockholders will not be able to attend the HF Sinclair Special Meeting in-person.

Even if you plan to virtually attend the HF Sinclair Special Meeting, to ensure that your shares of HF Sinclair Common Stock will be represented at the HF Sinclair Special Meeting, you are encouraged to promptly sign, date and return the enclosed proxy card (a proxy card and a postage-paid envelope are enclosed for your convenience) or grant your proxy electronically over the Internet or by telephone (using the instructions found on the proxy card). If you virtually attend the HF Sinclair Special Meeting and vote at the HF Sinclair Special Meeting, your vote will revoke any proxy previously submitted.

If your shares of HF Sinclair Common Stock are held in “street name,” see the answer below for pertinent information regarding how to ensure your shares of HF Sinclair Common Stock are voted.

You will need the 16-digit control number found on your proxy card or voting instruction form in order to participate in the HEP Special Meeting (including voting your HEP Common Units). As the HEP Special Meeting is virtual, there will be no physical meeting location and HEP Unitholders will not be able to attend the HEP Special Meeting in-person.

Even if you plan to virtually attend the HEP Special Meeting, to ensure that your HEP Common Units will be represented at the HEP Special Meeting, you are encouraged to promptly sign, date and return the enclosed proxy card (a proxy card and a postage-paid envelope are enclosed for your convenience) or grant your proxy electronically over the Internet or by telephone (using the instructions found on the proxy card). If you virtually attend the HEP Special Meeting and vote at the HEP Special Meeting, your vote will revoke any proxy previously submitted.

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If your HEP Common Units are held in “street name,” see the answer below for pertinent information regarding how to ensure your HEP Common Units are voted.

Failure of a HF Sinclair Stockholder to instruct its, his or her bank, broker or other nominee how such stockholder wishes to vote its, his or her shares will have no effect on the outcome of the HF Sinclair Stock Issuance Proposal, assuming the presence of a quorum at the HF Sinclair Special Meeting, or on the outcome of the HF Sinclair Adjournment Proposal.

Failure of a HEP Unitholder to instruct its, his or her bank, broker or other nominee how such unitholder wishes to vote its, his or her units will be the same as a vote “AGAINST” the Merger Proposal. Failure of a HEP Unitholder to instruct its, his or her bank, broker or other nominee how such unitholder wishes to vote its, his or her units will have no effect on the outcome of the HEP Adjournment Proposal, assuming the absence of a quorum. If a quorum is present, failure of a HEP Unitholder to instruct its, his or her bank, broker or other nominee how such HEP Unitholder wishes to vote its, his or her units will be the same as a vote “AGAINST” the HEP Adjournment Proposal.

You may also vote at the HF Sinclair Special Meeting or the HEP Special Meeting, as applicable, if you provide a “legal proxy” from your bank, broker or other nominee giving you the right to vote your HF Sinclair Common Stock or HEP Common Units, as applicable, at the HF Sinclair Special Meeting or the HEP Special Meetings, as applicable.

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On August 15, 2023, among other things, the HF Sinclair Board (acting, in part, based upon the recommendation of the HF Sinclair Conflicts Committee) unanimously (i) determined that the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, are advisable and in the best interests of HF Sinclair and the HF Sinclair Stockholders, (ii) approved the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, (iii) directed that the HF Sinclair Stock Issuance be submitted to a vote of the HF Sinclair Stockholders for approval at the HF Sinclair Special Meeting and (iv) resolved to recommend approval of the HF Sinclair Stock Issuance by the HF Sinclair Stockholders at the HF Sinclair Special Meeting.

The HF Sinclair Board and HF Sinclair Conflicts Committee unanimously recommend that the HF Sinclair Stockholders vote “FOR” the HF Sinclair Stock Issuance Proposal. The HF Sinclair Board unanimously recommends that the HF Sinclair Stockholders vote “FOR” the HF Sinclair Adjournment Proposal.

The HF Sinclair Stockholders should be aware that certain of the directors, executive officers and other affiliates of HF Sinclair may have interests in the Merger that are different from, or in addition to, the interests they may have as a HF Sinclair Stockholder. See “Special Factors—Interests of Certain Persons in the Merger.”

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Following the HEP Conflicts Committee meeting, the GP Board held a special meeting and, acting upon the recommendation of the HEP Conflicts Committee, unanimously (i) determined that the Merger Agreement and the transactions contemplated thereby are in the best interests of HEP, including the HEP Unaffiliated Unitholders, (ii) approved the Merger Agreement and the transactions contemplated thereby on the terms and subject to the conditions set forth in the Merger Agreement, and (iii) resolved to (a) direct that the Merger Agreement and the Merger be submitted to a vote of the HEP Unitholders for approval pursuant to Section 14.3 of the HEP Partnership Agreement and (b) recommend the approval of the Merger Agreement and the Merger by the HEP Unitholders at the HEP Special Meeting.

The HEP Conflicts Committee and the GP Board recommend that the HEP Unitholders vote “FOR” the Merger Proposal. The GP Board recommends that the HEP Unitholders vote “FOR” the HEP Adjournment Proposal.

For more information regarding the approval of the HEP Conflicts Committee and the GP Board in making such determination under the HEP Partnership Agreement, see “Special Factors—Recommendations of the HEP Conflicts Committee and the GP Board and the Reasons for their Recommendations.”

The HEP Unitholders should be aware that certain of the directors, executive officers and other affiliates of the General Partner and certain members of the HEP Conflicts Committee may have interests in the Merger that are different from, or in addition to, the interests they may have as a HEP Unitholder. See “Special Factors—Interests of Certain Persons in the Merger.”

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If you are a HEP Unitholder and sign and return your proxy or voting instruction card without indicating how to vote on any particular proposal, the HEP Common Units represented by your proxy will be voted as recommended by the GP Board with respect to that proposal. This means they will be voted: (1) “FOR” the Merger Proposal and (2) “FOR” the HEP Adjournment Proposal.

An abstention occurs when a HF Sinclair Stockholder or a HEP Unitholder returns a proxy with an “abstain” instruction.

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HF Sinclair Corporation

2828 N. Harwood, Suite 1300

Dallas, Texas 75201

Attention: Secretary

Telephone: (214) 871-3555

Your presence without voting at the HF Sinclair Special Meeting will not automatically revoke your proxy, and any revocation of a proxy will not in any way affect your right to attend the HF Sinclair Special Meeting. If you hold your HF Sinclair Common Stock in “street name,” you should contact your bank, broker or other nominee for instructions regarding how to change your vote. You may also vote at the HF Sinclair Special Meeting if you provide a “legal proxy” from your bank, broker or other nominee giving you the right to vote your HF Sinclair Common Stock at the HF Sinclair Special Meeting.

Holly Energy Partners, L.P.

2828 N. Harwood, Suite 1300

Attention: Secretary

Dallas, Texas 75201

Telephone: (214) 871-3555

Your presence without voting at the HEP Special Meeting will not automatically revoke your proxy, and any revocation of a proxy will not in any way affect your right to attend the HEP Special Meeting. If you hold your HEP Common Units in “street name,” you should contact your bank, broker or other nominee for instructions regarding how to change your vote. You may also vote at the HEP Special Meeting if you provide a “legal proxy” from your bank, broker or other nominee giving you the right to vote your HEP Common Units at the HEP Special Meeting.

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MacKenzie Partners, Inc.

1407 Broadway

New York, New York 10018

Call (212) 929-5500 / Toll-Free: (800) 322-2885

Email: proxy@mackenziepartners.com

If you are a HEP Unitholder and have questions about the HEP Special Meeting or the Merger, or desire additional copies of this joint proxy statement/prospectus or additional proxy cards, you may contact:

MacKenzie Partners, Inc.

1407 Broadway

New York, New York 10018

Call (212) 929-5500 / Toll-Free: (800) 322-2885

Email: proxy@mackenziepartners.com

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RISK FACTORS

In addition to the other information included and incorporated by reference into this joint proxy statement/prospectus, including the matters addressed in the section titled “Cautionary Statement Regarding Forward-Looking Statements,” you should carefully consider the following risks before deciding whether to vote for the approval of the applicable proposals described in this joint proxy statement/prospectus. In addition, you should read and carefully consider the risks associated with each of HF Sinclair and HEP and their respective businesses. These risks can be found in HF Sinclair’s and HEP’s respective Annual Reports on Form 10-K for the year ended December 31, 2022, as updated by subsequent Quarterly Reports on Form 10-Q, all of which are filed with the SEC and incorporated by reference into this joint proxy statement/prospectus. For further information regarding the documents incorporated into this joint proxy statement/prospectus by reference, please see the section titled “Where You Can Find More Information” beginning on page 184. Realization of any of the risks described below, any of the events described under “Cautionary Statement Regarding Forward-Looking Statements” or any of the risks or events described in the documents incorporated by reference could have a material adverse effect on HF Sinclair’s, HEP’s or the combined organization’s businesses, financial condition, cash flows and results of operations and could result in a decline in the trading prices of the HF Sinclair Common Stock or the HEP Common Units.

Risks Related to the Merger

The Merger is subject to conditions, including some conditions that may not be satisfied on a timely basis, if at all. Failure to complete the Merger, or significant delays in completing the Merger, could negatively affect the trading prices of HF Sinclair Common Stock and HEP Common Units.

The completion of the Merger is not assured and is subject to certain risks, some of which are beyond the parties’ control, including the risk that certain conditions of the Merger Agreement are not satisfied or waived, which may prevent, delay or otherwise result in the Merger not occurring. These conditions include, among other things, HEP Unitholder Approval of the Merger Agreement, HF Sinclair Stockholder Approval of the HF Sinclair Stock Issuance and the expiration or termination of any applicable waiting periods under the HSR Act (the 30-day HSR waiting period expired on October 10, 2023, at 11:59 PM Eastern time). HF Sinclair and HEP cannot predict with certainty whether and when any of these conditions will be satisfied. Failure to complete, or significant delays in completing, the Merger could negatively affect the trading prices of HF Sinclair Common Stock and HEP Common Units. See “The Merger Agreement—Conditions to Completion of the Merger.”

Because the Exchange Ratio under the Merger Agreement is fixed and because the market price of HF Sinclair Common Stock will fluctuate prior to the completion of the Merger, HEP Public Unitholders cannot be sure of the market value of the HF Sinclair Common Stock they will receive as Merger Consideration relative to the value of HEP Common Units they exchange.

The market value of the consideration that the HEP Public Unitholders will receive in the Merger will depend, in part, on the trading price of HF Sinclair Common Stock at the closing of the Merger. The Exchange Ratio that determines the number of shares of HF Sinclair Common Stock that HEP Public Unitholders will receive (in addition to $4.00 in cash, without interest) in the Merger is fixed at 0.315 shares of HF Sinclair Common Stock for each HEP Common Unit (subject to adjustments in accordance with the terms of the Merger Agreement), which means that it will not change between now and the closing date, regardless of whether the market price of either HF Sinclair Common Stock or HEP Common Units changes. Stock or unit price changes may result from a variety of factors (many of which are beyond HF Sinclair’s and HEP’s control), including but not limited to:

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If the price of HF Sinclair Common Stock at the closing of the Merger is less than the price of HF Sinclair Common Stock on the date that the Merger Agreement was executed, then the market value of the Merger Consideration will be less than contemplated at the time the Merger Agreement was executed.

HF Sinclair and HEP will each be subject to business uncertainties while the Merger is pending, which could adversely affect their respective businesses.

Uncertainty about the effect of the Merger on the business relationships or commercial arrangements for the companies that do business with HF Sinclair and HEP may have an adverse effect on HF Sinclair and HEP’s respective businesses. These uncertainties may impair the ability of both HF Sinclair and HEP to attract, retain and motivate key personnel until the Merger is completed and for a period of time thereafter, and could cause those that transact with HF Sinclair and HEP to seek to change their existing business relationships.

If the Merger is approved by the HEP Unitholders, the date that HEP Public Unitholders will receive the Merger Consideration is dependent on the completion date of the Merger, which is uncertain.

As described in this joint proxy statement/prospectus, completing the proposed Merger is subject to several conditions, not all of which are controllable by HF Sinclair or HEP. Accordingly, if the proposed Merger is approved by the HEP Unitholders, the date that HEP Public Unitholders will receive the Merger Consideration depends on the completion date of the Merger, which is uncertain and subject to several other closing conditions.

The Merger Agreement limits HF Sinclair’s ability to pursue alternatives to the Merger, which may discourage other companies from making a favorable alternative transaction proposal and, in specified circumstances, could require HF Sinclair or HEP to pay the other party a termination fee.

Under the Merger Agreement, (i) the HF Sinclair Conflicts Committee and the HF Sinclair Board, based on the HF Sinclair Conflicts Committee’s recommendation, have recommended that the HF Sinclair Stockholders vote in favor of the HF Sinclair Stock Issuance and (ii) the HEP Conflicts Committee and the GP Board have recommended that the HEP Unitholders vote in favor of the Merger Agreement and the Merger. Under the Merger Agreement, if any of the HF Sinclair Board, the GP Board or their respective conflicts committees, withdraws, modifies or qualifies, or proposes publicly to withdraw, modify or qualify its recommendation with respect to the HF Sinclair Stock Issuance Proposal and the Merger Proposal, as applicable, unless the Merger Agreement has been terminated in accordance with its terms, HF Sinclair and HEP, as applicable, will still be required to submit the HF Sinclair Stock Issuance Proposal and the Merger Proposal, respectively, to a vote at their respective special meetings. In addition, under the Merger Agreement, HF Sinclair and HEP generally have an opportunity to offer to modify the terms of the Merger Agreement before the other party’s board or conflicts committee may withdraw or qualify its recommendation. For more information, see the sections entitled “The Merger Agreement—HF Sinclair Recommendation and HF Sinclair Adverse Recommendation Change” and “The Merger Agreement—The General Partner Recommendation and HEP Adverse Recommendation Change.” The Merger Agreement further provides that, if HEP or HF Sinclair terminates the Merger Agreement in response to an adverse recommendation change by the other party’s board or conflicts committee, HEP may be required to pay HF Sinclair a breakup fee of $10.0 million or HF Sinclair may be required to pay HEP a breakup fee of $20.0 million, as applicable. See “The Merger Agreement — Effect of Termination; Termination Expenses” for additional details.

These provisions regarding a HF Sinclair adverse recommendation change could discourage a potential third-party acquirer or other strategic transaction partner that might have an interest in HF Sinclair from considering or

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pursuing an alternative transaction with HF Sinclair. These provisions might also result in a potential third-party acquirer or other strategic transaction partner proposing to pay a lower price than it might otherwise have proposed to pay because of the added expense of the termination fee that may become payable in certain circumstances.

HF Sinclair and HEP may incur substantial transaction-related costs in connection with the Merger.

HF Sinclair and HEP expect to incur substantial nonrecurring expenses in connection with completing the Merger, including fees paid to legal, financial and accounting advisors, filing fees, proxy solicitation costs and printing costs. Many of the expenses that will be incurred, by their nature, are difficult to estimate accurately at the present time. Pursuant to the Merger Agreement, all fees and expenses incurred in connection with the Transactions will be paid by the respective party incurring such fees and expenses except that expenses (other than the expenses of financial advisors or outside legal advisors) relating to the preparation, printing, filing and mailing of this joint proxy statement/prospectus and the related Schedule 13E-3 will be paid 50% by HF Sinclair and 50% by HEP and costs and fees of the exchange agent and all expenses associated with the exchange process will be paid by HF Sinclair.

If the Merger Agreement is terminated, under certain circumstances, HF Sinclair or HEP may be obligated to reimburse the other party for costs incurred related to the Merger or pay a termination fee to the other party.

Upon termination of the Merger Agreement under certain circumstances, HEP may be obligated to reimburse HF Sinclair for its expenses, up to a maximum amount of $5.0 million, or pay HF Sinclair a termination fee in an amount in cash equal to $10.0 million. Further, upon termination of the Merger Agreement under certain circumstances, HF Sinclair may be obligated to reimburse HEP for its expenses, up to a maximum amount of $5.0 million, or pay HEP a termination fee in an amount in cash equal to $20.0 million. See “The Merger Agreement—Effect of Termination; Termination Expenses.”

HF Sinclair and HEP may in the future be targets of securities class action and derivative lawsuits, which could result in substantial costs and may delay or prevent the closing of the Merger.

Securities class action lawsuits and derivative lawsuits are often brought against companies that have entered into merger agreements in an effort to enjoin the relevant merger or seek monetary relief. HF Sinclair and HEP may in the future be defendants in one or more lawsuits relating to or arising out of the Merger Agreement and the Merger. HF Sinclair and HEP cannot predict the outcome of these lawsuits, or others, nor can either company predict the amount of time and expense that will be required to resolve such litigation. An unfavorable resolution of any such litigation surrounding the Merger could delay or prevent its consummation. In addition, the costs of defending the litigation, even if resolved in HF Sinclair’s and HEP’s favor, could be substantial, and such litigation could divert management time and resources of HF Sinclair and HEP from pursuing the consummation of the Merger and other potentially beneficial business opportunities.

HEP Unitholders will not be entitled to appraisal rights in connection with the Merger.

Under the Delaware LP Act, only contractual rights to appraisal are available for unitholders, so appraisal rights will only be available for limited partners if such rights are provided in the partnership agreement. The HEP Partnership Agreement does not provide for appraisal rights to HEP Unitholders. Accordingly, HEP Unitholders do not have appraisal rights. See “Special Factors—No Appraisal Rights.”

HF Sinclair and HEP must obtain certain regulatory approvals and clearances to consummate the Merger, which, if delayed, not granted or granted with unacceptable conditions, could prevent, substantially delay or impair consummation of the Merger, result in additional expenditures of money and resources or reduce the anticipated benefits of the Merger.

The completion of the Merger is subject to antitrust review in the United States. Under the HSR Act and the rules promulgated thereunder, the Merger cannot be completed until the parties to the Merger Agreement have given

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notification and furnished information to the FTC and the DOJ, and until the applicable waiting period has expired or has been terminated. On September 7, 2023, HF Sinclair and HEP filed the required notice and furnished the required information under the HSR Act to the Antitrust Division of the DOJ and the FTC. On October 10, 2023, at 11:59 PM Eastern time, the 30-day HSR waiting period expired.

At any time before or after consummation of the Merger, the Antitrust Division of the DOJ or the FTC, or any state, could take any action under the antitrust laws as it deems necessary or desirable in the public interest. Private parties may also seek to take legal action under the antitrust laws under certain circumstances. Such conditions or changes and the process of obtaining regulatory approvals could have the effect of delaying or impeding consummation of the Merger or of imposing additional costs or limitations on HF Sinclair or HEP following completion of the Merger, any of which might have an adverse effect on HF Sinclair or HEP following completion of the Merger and may diminish the anticipated benefits of the Merger. See “The Merger Agreement—Conditions to Completion of the Merger.”

Certain executive officers and directors of the General Partner and HF Sinclair have interests in the Merger that are different from, or in addition to, the interests they may have as a HEP Unitholder or a HF Sinclair Stockholder, respectively, which could have an influence on their decision to support or approve the Merger.

Certain executive officers and directors of the General Partner own equity interests in HF Sinclair, receive fees and other compensation from HF Sinclair, and have rights to ongoing indemnification and insurance coverage by HF Sinclair (as executives and, in Mr. Lee’s case, as a director of HF Sinclair) and HEP and will have rights to indemnification and insurance coverage by the Surviving Entity, with respect to HEP’s existing directors’ and officers’ liability insurance policy, that give them interests in the Merger that may be different from, or be in addition to, interests of the HEP Unaffiliated Unitholders.

Additionally, certain executive officers and directors of HF Sinclair beneficially own HEP Common Units and will receive the applicable Merger Consideration upon completion of the Merger, receive fees and other compensation from HF Sinclair, and are entitled to indemnification arrangements with HF Sinclair that give them interests in the Merger that may be different from, or be in addition to, interests of the HF Sinclair Stockholders.

These different interests are described in “Special Factors—Interests of Certain Persons in the Merger.”

REH Company will increase its holdings of HF Sinclair Common Stock following the completion of the Merger and may have ability to influence HF Sinclair’s management and affairs.

As of October 12, 2023, REH Company owned approximately 13.0% of the outstanding HF Sinclair Common Stock, and has the right under the REH Stockholders Agreement and the REH Unitholders Agreement to nominate two directors to the HF Sinclair Board and one director to the GP Board, respectively. REH Company is currently HF Sinclair’s largest stockholder.

So long as REH Company continues to control a significant amount of HF Sinclair Common Stock, it will continue to be able to influence all matters requiring stockholder approval, subject to the voting agreements of the REH Parties set forth in the REH Stockholders Agreement. Moreover, this concentration of stock ownership may also adversely affect the trading price of HF Sinclair Common Stock to the extent investors perceive a disadvantage in owning stock of a company with a significant stockholder.

Upon completion of the Merger, assuming there is no decrease in REH Company’s holdings of HF Sinclair Common Stock and HEP Common Units prior to completion of the Merger, REH Company would be expected to own approximately 14.9% of both outstanding HF Sinclair Common Stock and HF Sinclair’s combined voting power. As a result, REH Company will retain certain rights under the REH Stockholders Agreement with HF Sinclair, including (i) the ability to nominate two directors to the HF Sinclair Board in the event that REH Company continues to own at least 15% of the outstanding HF Sinclair Common Stock upon completion of the

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Merger and (ii) the ability to nominate one director to the HF Sinclair Board in the event that REH Company continues to own less than 15% but more than or equal to 5% of the outstanding HF Sinclair Common Stock upon completion of the Merger. Further, the existence of a significant stockholder may have the effect of deterring hostile takeovers, delaying or preventing changes in control or changes in management, or limiting the ability of HF Sinclair’s other stockholders to approve transactions that they may view as being in their best interests or in the best interests of HF Sinclair.

In the event that REH Company continues to be the owner of a significant amount of HF Sinclair Common Stock, the prospect that it may be able to influence matters requiring the approval of HF Sinclair Stockholders may continue. In any of these matters, the interests of REH Company may differ or conflict from those of other HF Sinclair Stockholders. Moreover, in the event that REH Company continues to be the owner of a significant concentration of HF Sinclair Common Stock, such an ownership stake may also adversely affect the trading price of HF Sinclair Common Stock to the extent investors perceive a disadvantage in owning stock of a company with a significant stockholder.

Additionally, on June 14, 2023, certain lock-up provisions that restricted REH Company’s ability to transfer its shares of HF Sinclair Common Stock and HEP Common Units, as applicable, under the REH Stockholders Agreement and the REH Unitholders Agreement expired. As a result, and subject to the filing of a resale registration statement or satisfaction of the requirements of Rule 144 under the Securities Act, REH Company and its stockholders may seek to sell their shares of HF Sinclair Common Stock and HEP Common Units, as applicable. Such sales (or the perception that sales may occur) may affect the market for, and the market price of, the HF Sinclair Common Stock and HEP Common Units in an adverse manner.

The opinion of Intrepid speaks only as of the date rendered based on circumstances and conditions existing as of the signing of the Merger Agreement and will not reflect changes in circumstances between the signing of the Merger Agreement and the closing date of the Merger.

The HEP Conflicts Committee received an opinion from its financial advisor, Intrepid, in connection with the signing of the Merger Agreement based on circumstances and conditions existing at that time but has not obtained any updated opinion from its financial advisor as of the date of this joint proxy statement/prospectus. Changes in the operations and prospects of HF Sinclair and HEP, general market and economic conditions and other factors that may be beyond the control of HF Sinclair or HEP, and on which Intrepid’s opinion was based, may significantly alter the value of HF Sinclair and/or HEP or the prices of HF Sinclair’s Common Stock or HEP’s Common Units by the time the Merger is completed. The opinion speaks only as of the date rendered and, accordingly, does not address the fairness of the Merger Consideration from a financial point of view as of any date other than the date of such opinion, including upon completion of the Merger. Because the HEP Conflicts Committee does not currently anticipate asking its financial advisor to update its opinion, the opinion will not address the fairness of the Merger Consideration from a financial point of view at the time the Merger is completed. For a description of the opinion that the HEP Conflicts Committee received from its financial advisor, see the section entitled “Special Factors—Opinion of the Financial Advisor to the HEP Conflicts Committee.” A copy of the opinion of Intrepid is attached as Annex B to this joint proxy statement/prospectus.

Financial projections by HF Sinclair and HEP may not prove to be reflective of actual future results.

In connection with the Merger, HF Sinclair management and the General Partner’s management prepared and considered, among other things, internal financial forecasts for HF Sinclair and HEP. These forecasts speak only as of the date made and will not be updated. These financial projections were not provided with a view to public disclosure, are subject to significant economic, competitive, industry and other uncertainties and may not be achieved in full, at all or within projected timeframes. In addition, the failure of businesses to achieve projected results could have a material adverse effect on the share price of HF Sinclair Common Stock and on HF Sinclair’s financial position and ability to maintain or increase its dividends following the Merger.

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The HEP Partnership Agreement limits the duties of the General Partner and HLH to the HEP Unitholders and restricts the remedies available to the HEP Unitholders for actions taken by the General Partner or HLH that might otherwise constitute breaches of its duties.

As permitted under the HEP Partnership Agreement, due to the potential conflicts of interest between HF Sinclair and the General Partner, on the one hand, and HEP and the HEP Unaffiliated Unitholders, on the other hand, the GP Board submitted the Merger and related matters to the HEP Conflicts Committee for, among other things, review, evaluation, negotiation and possible approval of a majority of its members, which is referred to as “Special Approval” in the HEP Partnership Agreement and this joint proxy statement/prospectus. The duties of the General Partner, the GP Board and the HEP Conflicts Committee to the HEP Unitholders in connection with the Merger are substantially limited by the HEP Partnership Agreement, pursuant to which:

The HEP Conflicts Committee reviewed, negotiated and evaluated the Merger Agreement and the transactions contemplated thereby, including the Merger, on behalf of HEP and the HEP Unaffiliated Unitholders. On August 15, 2023, the HEP Conflicts Committee unanimously and in good faith (i) determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are in the best interests of HEP, including the HEP Unaffiliated Unitholders, (ii) approved the Merger Agreement and the transactions contemplated thereby, including the Merger (the foregoing constituting “Special Approval” for all purposes of the HEP Partnership Agreement, including Section 7.9(a) thereof) on the terms and subject to the conditions set forth in the Merger Agreement, (iii) recommended that the GP Board approve the Merger Agreement and the transactions contemplated thereby, including the Merger, on the terms and subject to the conditions set forth in the Merger Agreement, and (iv) resolved and recommended that the GP Board resolve to (a) direct that the Merger Agreement and the Merger be submitted to a vote of the HEP Unitholders for approval and (b) recommend approval of the Merger Agreement and the Merger by the HEP Unitholders at the HEP Special Meeting. Following the HEP Conflicts Committee meeting, the GP Board held a special meeting and, acting upon the recommendation of the HEP Conflicts Committee, unanimously (i) determined that the Merger Agreement and the transactions contemplated thereby are in the best interests of HEP, including the HEP Unitholders, (ii) approved the Merger Agreement and the transactions contemplated thereby on the terms and subject to the conditions set forth in the Merger Agreement, and (iii) resolved to (a) direct that the Merger Agreement and the Merger be submitted to a vote of the HEP Unitholders for approval pursuant to Section 14.3 of the HEP Partnership Agreement and (b) recommend the approval of the Merger Agreement and the Merger by the HEP Unitholders at the HEP Special Meeting.

Risks Inherent in an Investment in HF Sinclair

Shares of HF Sinclair Common Stock to be received by HEP Public Unitholders as a result of the Merger have different rights from HEP Common Units.

Following completion of the Merger, HEP Public Unitholders will no longer hold HEP Common Units, but will instead be HF Sinclair Stockholders. There are important differences between the rights of the HEP Unitholders and the rights of the HF Sinclair Stockholders. Ownership interests in a limited partnership are fundamentally different from ownership interests in a corporation. The HEP Unitholders will own HF Sinclair Common Stock following the completion of the Merger, and their rights associated with the HF Sinclair Common Stock will be governed by the HF Sinclair Charter, the HF Sinclair Bylaws and the DGCL, which differ in a number of

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respects from the HEP Partnership Agreement and the Delaware LP Act. See “Comparison of the Rights of the HF Sinclair Stockholders and the HEP Unitholders.”

The market value of HF Sinclair Common Stock could decline if large amounts of such HF Sinclair Common Stock are sold following the Merger and the market value of HF Sinclair Common Stock could also decline as a result of issuances and sales of shares of HF Sinclair Common Stock other than in connection with the Merger.

Following completion of the Merger, HEP Public Unitholders will no longer hold HEP Common Units, and will own interests in a combined company operating an expanded business with more assets and a different mix of liabilities. Current HF Sinclair Stockholders and former HEP Public Unitholders may not wish to continue to invest in the combined company, or may wish to reduce their investment in the combined company, in order to comply with institutional investing guidelines, to increase diversification or to track any rebalancing of stock indices in which HF Sinclair Common Stock or HEP Common Units are or were included. If, following the completion of the Merger, large amounts of HF Sinclair Common Stock are sold, the price of HF Sinclair Common Stock could decline.

Furthermore, HF Sinclair cannot predict the effect that issuances and sales of shares of HF Sinclair Common Stock, whether taking place before completion of the Merger (subject to the limitations of the Merger Agreement) or after completion of the Merger, including issuances and sales in connection with capital markets transactions, acquisition transactions or other transactions, may have on the market value of HF Sinclair Common Stock. The issuance and sale of substantial amounts of HF Sinclair Common Stock could adversely affect its market value.

HF Sinclair may not achieve the intended benefits of the Merger, and the Merger may disrupt its current plans or operations.

There can be no assurance that HF Sinclair will be able to realize the expected benefits of the Merger (including related synergies). The integration of the two companies may result in material challenges, including the diversion of management’s attention from ongoing business concerns; retaining or attracting business and operational relationships; the possibility of faulty assumptions underlying expectations regarding the integration process and associated expenses; consolidating corporate and administrative infrastructures; as well as potential unknown liabilities, unforeseen expenses relating to integration, or delays associated with the Merger.

Tax Risks Related to the Merger and the Ownership of HF Sinclair Common Stock Received in the Merger

In addition to reading the following risk factors, you are urged to read the section “United States Federal Income Tax Consequences” for a more complete discussion of the expected U.S. federal income tax consequences of the Merger and owning and disposing of HF Sinclair Common Stock received in the Merger.

The Merger will be a taxable transaction and, accordingly, the resulting tax liability of a HEP Public Unitholder, if any, will depend on the HEP Public Unitholder’s particular situation. The tax liability of a HEP Public Unitholder as a result of the Merger could be more than expected.

The receipt of HF Sinclair Common Stock and cash in exchange for HEP Public Common Units pursuant to the Merger Agreement will be a taxable transaction for U.S. federal income tax purposes. Accordingly, as a result of the Merger, a HEP Public Unitholder will recognize gain or loss for U.S. federal income tax purposes equal to the difference between such HEP Public Unitholder’s amount realized and the HEP Public Unitholder’s adjusted tax basis in their HEP Public Common Units. The amount of gain or loss recognized by each HEP Public Unitholder in the Merger will vary depending on each HEP Public Unitholder’s particular situation, including the value of the shares of HF Sinclair Common Stock and the amount of cash received by each HEP Public

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Unitholder in the Merger, the adjusted tax basis of the HEP Public Common Units exchanged by each HEP Public Unitholder in the Merger, and the amount of any suspended passive losses that may be available to a particular HEP Public Unitholder to offset a portion of the gain recognized by the HEP Public Unitholder.

Because the value of any HF Sinclair Common Stock received in the Merger will not be known until the Effective Time, a HEP Public Unitholder will not be able to determine its amount realized, and therefore its taxable gain or loss, until such time. In addition, because prior distributions in excess of a HEP Public Unitholder’s allocable share of HEP’s net taxable income decrease the HEP Public Unitholder’s tax basis in its HEP Public Common Units, the amount, if any, of the prior excess distributions with respect to such HEP Public Common Units will, in effect, become taxable income to a HEP Public Unitholder if the aggregate value of the consideration received in the Merger is greater than the HEP Public Unitholder’s adjusted tax basis in its HEP Public Common Units, even if the aggregate value of the consideration received in the Merger is less than the HEP Public Unitholder’s original cost basis in its HEP Public Common Units. Furthermore, a portion of the amount realized in the Merger, which amount could be substantial, will be separately computed and taxed as ordinary income or loss to the extent attributable to “unrealized receivables,” including depreciation recapture, or “inventory items” owned by HEP and its subsidiaries.

For a more complete discussion of U.S. federal income tax consequences of the Merger, see “United States Federal Income Tax Consequences.”

The U.S. federal income tax treatment of owning and disposing of HF Sinclair Common Stock received in the Merger will be different than the U.S. federal income tax treatment of owning and disposing of HEP Common Units.

HEP is classified as a partnership for U.S. federal income tax purposes and, generally, is not subject to entity-level U.S. federal income taxes. Instead, each HEP Unitholder is required to take into account its respective share of HEP’s items of income, gain, loss and deduction in computing its federal income tax liability, even if no cash distributions are made by HEP to the HEP Unitholder. A pro rata distribution of cash by HEP to a HEP Unitholder who is a U.S. Holder is generally not taxable for U.S. federal income tax purposes unless the amount of cash distributed is in excess of the HEP Unitholder’s adjusted tax basis in its HEP Common Units.

In contrast, HF Sinclair is classified as a corporation for U.S. federal income tax purposes and is subject to U.S. federal income tax on its taxable income. A distribution of cash by HF Sinclair to a HF Sinclair Stockholder who is a U.S. Holder will generally be included in such HF Sinclair Stockholder’s income as ordinary dividend income to the extent of HF Sinclair’s current or accumulated “earnings and profits,” as determined under U.S. federal income tax principles. A portion of the cash distributed to HF Sinclair Stockholders by HF Sinclair after the Merger may exceed HF Sinclair’s current and accumulated earnings and profits. Cash distributions to a HF Sinclair Stockholder who is a U.S. Holder in excess of HF Sinclair’s current and accumulated earnings and profits will be treated as a non-taxable return of capital, reducing the adjusted tax basis in the HF Sinclair Stockholder’s HF Sinclair Common Stock and, to the extent the cash distribution exceeds the holder’s adjusted tax basis, as capital gain from the sale or exchange of such HF Sinclair Common Stock. See “United States Federal Income Tax Consequences” for a more complete discussion of the expected U.S. federal income tax consequences of owning and disposing of HF Sinclair Common Stock.

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SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF HEP

The SEC allows HEP to “incorporate by reference” information into this joint proxy statement/prospectus. This means that HEP can disclose important information by referring to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this joint proxy statement/prospectus. This joint proxy statement/prospectus and the information that HEP later files with the SEC may update and supersede the information incorporated by reference. The audited consolidated financial statements of HEP for the two years ended December 31, 2022 and 2021 are incorporated herein by reference to HEP’s Annual Report on Form 10-K for the year ended December 31, 2022 (the “HEP 2022 Form 10-K”), originally filed on February 28, 2023.

The following tables present selected consolidated financial and operating information for HEP. HEP’s summary of consolidated statements of operations presented below for the years ended December 31, 2022 and 2021 and HEP’s summary of consolidated balance sheets presented below as of December 31, 2022 and 2021 have been derived from HEP’s audited consolidated financial statements, which are included in the HEP 2022 Form 10-K. HEP’s summary of consolidated statements of operations presented below for the six months ended June 30, 2023 and 2022 and HEP’s summary of consolidated balance sheets presented below as of June 30, 2023 have been derived from HEP’s financial results for the quarterly period ended June 30, 2023, which are included in HEP’s Quarterly Report on Form 10-Q filed with the SEC on August 3, 2023. You should read the following data in conjunction with the consolidated financial statements and the related notes thereto set forth in the HEP 2022 Form 10-K and in conjunction with the financial results from the quarter ended June 30, 2023 included in HEP’s Quarterly Report on Form 10-Q filed with the SEC on August 3, 2023, each of which is incorporated by reference into this joint proxy statement/prospectus. See “Where You Can Find More Information.”

HEP’s historical results do not necessarily indicate results expected for any future periods. The selected consolidated financial and operating information below should be read in conjunction with, and is qualified in its entirety by reference to, HEP’s audited consolidated financial statements and unaudited consolidated financial statements for the six months ended June 30, 2023 and the related notes and other financial information, which are also incorporated into this joint proxy statement/prospectus by reference. See “Where You Can Find More Information.”

Summary Consolidated Balance Sheets

(In thousands)

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Summary Consolidated Statements of Income

(In thousands, except per unit data)

HF Sinclair advises that the acquisition of HEP is not significant and, as such, pro forma information has not been provided pursuant to Item 5 of Form S-4.

Book Value per HEP Common Unit

As of June 30, 2023, the book value per HEP Common Unit was $7.48. Book value per HEP Common Unit is computed by dividing total equity of $945.6 million as of June 30, 2023 by the total HEP Common Units outstanding on that date of 126,440,201 HEP Common Units.

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COMPARATIVE MARKET PRICES AND CASH DIVIDEND/DISTRIBUTION INFORMATION

Shares of HF Sinclair Common Stock are traded on the NYSE under the trading symbol “DINO” and the HEP Common Units are traded on the NYSE under the trading symbol “HEP.” On August 15, 2023, the last trading day before the public announcement of the parties entering into the Merger Agreement, the reported closing price of shares of HF Sinclair Common Stock and HEP Common Units on the NYSE was $56.22 per share of HF Sinclair Common Stock and $21.30 per HEP Common Unit. As of August 15, 2023, the equivalent per unit value of the HF Sinclair Common Stock included in the Merger Consideration for each HEP Common Unit, which per unit value is calculated as (i) the product of (a) the applicable HF Sinclair Common Stock closing price and (b) the Exchange Ratio plus (ii) $4.00 was $21.71. The receipt of Merger Consideration in exchange for HEP Public Common Units pursuant to the Merger will be a taxable transaction to HEP Public Unitholders. See “United States Federal Income Tax Consequences.” On     , 2023, the most recent practicable date before the printing of this joint proxy statement/prospectus, the reported closing price of shares of HF Sinclair Common Stock and HEP Common Units on the NYSE was $     per share of HF Sinclair Common Stock and $     per HEP Common Unit. As of     , 2023, the equivalent per unit value of the Merger Consideration for each HEP Common Unit, which per unit value is calculated as (i) the product of (a) the applicable HF Sinclair Common Stock closing price and (b) the Exchange Ratio plus (ii) $4.00 is $    .

On     , 2023, the most recent practicable date before the printing of this joint proxy statement/prospectus, high and low reported sales prices of HEP Common Units were $     and $    , respectively, and there were approximately      holders of record of HEP Common Units.

On     , 2023, the most recent practicable date before the printing of this joint proxy statement/prospectus, high and low reported sales prices of shares of HF Sinclair Common Stock were $     and $    , respectively, and there were approximately      holders of record of HF Sinclair Common Stock.

The following table shows the high and low prices per share of HF Sinclair Common Stock and per HEP Common Unit as well as the cash dividend paid per share of HF Sinclair Common Stock and cash distribution paid per HEP Common Unit, each as reported by the NYSE, during the periods indicated.

The above table may not provide meaningful information to the HEP Unitholders in connection with making any decisions with respect to the Merger. The HEP Unitholders are urged to obtain current market quotations for

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shares of HF Sinclair Common Stock and HEP Common Units and to review carefully the other information contained in this joint proxy statement/prospectus or incorporated herein by reference in making any decisions with respect to the Merger. See “Where You Can Find More Information” for instructions on how to obtain the information that has been incorporated by reference. Historical performance is not necessarily indicative of any performance to be expected in the future. See “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements.”

Prior Stock Purchases

The following table sets forth information about HEP Common Units purchased by HEP during the past two years. None of the Parent Entities or the General Partner has purchased HEP Common Units during the past two years.

There have been no transactions in the last 60 days in the HEP Common Units by HEP, the General Partner or the Parent Entities or any executive officer, director, associate or majority-owned subsidiary of the foregoing parties or by any pension, profit-sharing or similar plan of the foregoing parties.

Dividend and Share Data—HF Sinclair

On February 23, 2023, the HF Sinclair Board declared a regular quarterly dividend in the amount of $0.45 per share of HF Sinclair Common Stock, which represented an increase of $0.05 over its previous dividend of $0.40 per share of HF Sinclair Common Stock. On August 2, 2023, the HF Sinclair Board declared a regular quarterly dividend in the amount of $0.45 per share of HF Sinclair Common Stock. HF Sinclair intends to consider the declaration of a dividend on a quarterly basis, although no assurance can be given as to future dividends since they are dependent upon future earnings, capital requirements, HF Sinclair’s financial condition and other factors.

As of October 12, 2023, there were approximately 181,042,806 shares of HF Sinclair Common Stock outstanding with approximately 1,602 holders of record of HF Sinclair Common Stock.

Distribution and Unit Data—HEP

The HEP Partnership Agreement provides that within 45 days following the end of each quarter, HEP will, subject to Section 17-607 of the Delaware LP Act, distribute an amount equal to 100% of Available Cash (as defined in the HEP Partnership Agreement) with respect to such quarter to the HEP Unitholders, pro rata, as of record on the applicable record date, which will be selected by the General Partner. As a result of the conversion and cancellation of HEP Public Common Units held by the HEP Public Unitholders in connection with the Merger, HEP will no longer make quarterly distributions to the HEP Public Unitholders following the closing of the Merger.

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During the term of the Merger Agreement until the Effective Time, the General Partner will cause HEP to pay a quarterly cash distribution to the HEP Unitholders (including the HEP Public Unitholders) consistent with past practice in an amount not less than $0.35 per HEP Common Unit per quarter. Neither HEP nor the General Partner shall be required to take any action with respect to a cash distribution if such action would violate applicable law or the HEP Partnership Agreement or any material contract to which HEP is a party as of August 15, 2023. See “The Merger Agreement—Dividends and Distributions.”

As of October 12, 2023, there were approximately 126,440,201 HEP Common Units outstanding and there were approximately 83 holders of record of HEP Common Units.

The Merger Agreement restricts the ability of HEP to declare, authorize, set aside or pay any distribution payable in cash, equity or property in respect of the HEP Common Units prior to the consummation of the Merger, other than payment of regular quarterly distributions that are declared and paid consistent with past practice and do not exceed $0.35 per HEP Common Unit per quarter. See “The Merger Agreement—Conduct of Business Prior to Closing.”

Because the Exchange Ratio is fixed and because the market price of HF Sinclair Common Stock will fluctuate prior to the completion of the Merger, the HEP Unitholders cannot be sure of the market value of the HF Sinclair Common Stock they will receive as Merger Consideration relative to the value of HEP Common Units they exchange. See “Risk Factors” beginning on page 22.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

The statements contained or incorporated by reference in this joint proxy statement/prospectus relating to matters that are not historical facts are forward-looking statements based on management’s beliefs and assumptions using currently available information and expectations as of the date hereof, are not guarantees of future performance and involve certain risks and uncertainties, including those contained in HF Sinclair’s and HEP’s filings with the SEC. Forward-looking statements use words such as “anticipate,” “project,” “will,” “expect,” “plan,” “goal,” “forecast,” “strategy,” “intend,” “should,” “would,” “could,” “believe,” “may,” and similar expressions and statements regarding HF Sinclair’s and HEP’s plans and objectives for future operations or the proposed Merger. Although HF Sinclair and HEP believe that the expectations reflected in these forward-looking statements are reasonable, neither HF Sinclair nor HEP can assure you that HF Sinclair’s and HEP’s expectations will prove correct. Therefore, actual outcomes and results could materially differ from what is expressed, implied or forecast in such statements. Any differences could be caused by a number of factors, including, but not limited to:

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You are cautioned that the foregoing list of important factors may not contain all of the material factors that are important to you. In evaluating these factors and our forward-looking statements, you should carefully consider the risks described herein and in the other reports that HF Sinclair and HEP file with the SEC. See the sections entitled “Risk Factors” beginning on page 22 of this joint proxy statement/prospectus and “Where You Can Find More Information” beginning on page 184 of this joint proxy statement/prospectus. In addition, in light of these risks and uncertainties, the matters referred to in the forward-looking statements contained in this joint proxy statement/prospectus may not in fact occur. Accordingly, investors should not place undue reliance on those statements.

Forward-looking statements included herein speak only as of the date of made and, other than as required by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. All subsequent written and oral forward-looking statements attributable to us or persons acting on our behalf are expressly qualified in their entirety by the foregoing.

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THE PARTIES

HF Sinclair Corporation

HF Sinclair is a corporation incorporated under the laws of the State of Delaware. HF Sinclair’s Common Stock is listed on the NYSE under the trading symbol “DINO.” HF Sinclair is an independent energy company that produces and markets high-value light products such as gasoline, diesel fuel, jet fuel, renewable diesel and other specialty products. HF Sinclair owns and operates refineries located in Kansas, Oklahoma, New Mexico, Washington, Utah and Wyoming. HF Sinclair markets its refined products principally in the Southwest United States, the Rocky Mountains extending into the Pacific Northwest and in other neighboring Plains states. HF Sinclair supplies high-quality fuels to more than 1,500 branded stations and licenses the use of the Sinclair brand at more than 300 additional locations throughout the country. In addition, subsidiaries of HF Sinclair produce and market base oils and other specialized lubricants in the U.S., Canada and the Netherlands, and export products to more than 80 countries. Through its subsidiaries, HF Sinclair produces renewable diesel at two of its facilities in Wyoming and also at its facility in Artesia, New Mexico. HF Sinclair also owns a 47% limited partner interest and a non-economic general partner interest in HEP, a master limited partnership that provides petroleum product and crude oil transportation, terminalling, storage and throughput services to the petroleum industry, including HF Sinclair subsidiaries.

HF Sinclair’s principal executive offices are located at 2828 N. Harwood, Suite 1300, Dallas, Texas 75201 and its telephone number is (214) 871-3555.

Navajo Pipeline Co., L.P.

HoldCo is a limited partnership organized under the laws of the State of Delaware and an indirect wholly owned subsidiary of HF Sinclair.

HoldCo’s principal executive offices are located at 2828 N. Harwood, Suite 1300, Dallas, Texas 75201 and its telephone number is (214) 871-3555.

Holly Apple Holdings LLC

Merger Sub, a wholly owned subsidiary of HoldCo, is a limited liability company formed under the laws of the State of Delaware on August 14, 2023, for the purpose of effecting the Merger. Upon completion of the Merger, Merger Sub will merge with and into HEP, with HEP surviving as an indirect wholly owned subsidiary of HF Sinclair. Merger Sub has not conducted any activities other than those incidental to its formation and the matters contemplated by the Merger Agreement.

Merger Sub’s principal executive offices are located at 2828 N. Harwood, Suite 1300, Dallas, Texas 75201 and its telephone number is (214) 871-3555.

Holly Logistic Services, L.L.C.

The General Partner is a limited liability company formed under the laws of the State of Delaware and is the general partner of HLH, and an indirect wholly owned subsidiary of HF Sinclair.

The General Partner’s principal executive offices are located at 2828 N. Harwood, Suite 1300, Dallas, Texas 75201 and its telephone number is (214) 871-3555.

HEP Logistics Holdings, L.P.

HLH is a limited partnership organized under the laws of the State of Delaware and is the general partner of HEP.

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HLH’s principal executive offices are located at 2828 N. Harwood, Suite 1300, Dallas, Texas 75201 and its telephone number is (214) 871-3555.

Holly Energy Partners, L.P.

HEP, together with its consolidated subsidiaries, is a publicly traded master limited partnership organized under the laws of the State of Delaware. HEP’s Common Units are listed on the NYSE under the trading symbol “HEP.” HEP provides petroleum product and crude oil transportation, terminalling, storage and throughput services to the petroleum industry, including subsidiaries of HF Sinclair. HEP, through its subsidiaries and joint ventures, owns and/or operates petroleum product and crude pipelines, tankage and terminals in Colorado, Idaho, Iowa, Kansas, Missouri, Nevada, New Mexico, Oklahoma, Texas, Utah, Washington and Wyoming, as well as refinery processing units in Kansas and Utah.

HEP’s principal executive offices are located at 2828 N. Harwood, Suite 1300, Dallas, Texas 75201 and its telephone number is (214) 871-3555.

During the past five years, none of the entities described above have been (i) convicted in a criminal proceeding, or (ii) party to any judicial or administrative proceeding (except for matters that were dismissed without sanction or settlement) that resulted in a judgment, decree or final order enjoining the entity from future violations of, or prohibiting activities subject to, federal or state securities laws, or a finding of any violation of federal or state securities laws.

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SPECIAL FACTORS

This section of the document describes the material aspects of the proposed Merger, but may not contain all of the information that is important to you. The following discussion of the Merger is qualified in its entirety by reference to the Merger Agreement between HF Sinclair and HEP. You are urged to carefully read the Merger Agreement in its entirety, a copy of which is attached as Annex A to this joint proxy statement/prospectus and incorporated by reference herein.

Overview of Special Factors

The proposed Merger is a “going-private” transaction under SEC rules and the Exchange Act. Accordingly, Rule 13e-3 and related rules under the Exchange Act require that the Parent Entities, HEP, HLH and the General Partner make certain disclosures regarding the Merger. This “Special Factors” section contains various information that you should read carefully. For example, the section entitled “ —Effects of the Merger” explains the material steps for completing the Merger and results of the Merger, including the Surviving Entity. The section entitled “ —Background of the Merger” explains, among other things, HF Sinclair’s purposes for the Merger and the general negotiation of the Merger Agreement. The sections entitled “ —Position of HF Sinclair, HoldCo and Merger Sub as to the Fairness of the Merger,” “ —Recommendations of the HF Sinclair Conflicts Committee and the HF Sinclair Board and the Reasons for the Merger” and “ —Recommendations of the HEP Conflicts Committee and the GP Board and the Reasons for their Recommendations,” respectively, explain why the HEP Conflicts Committee and the GP Board, and each of HEP, HLH, and the General Partner, on the one hand, and the Parent Entities, on the other hand, believe the Merger is in the best interests of the HEP Unaffiliated Unitholders. The section entitled “ —Financial Advisor Discussion Materials Provided to HF Sinclair” summarizes the process and methodologies followed by Barclays in acting as HF Sinclair’s financial advisor in connection with evaluating the Merger. The section entitled “ —Opinion of the Financial Advisor to the HEP Conflicts Committee” summarizes the process and methodologies followed by Intrepid in rendering its opinion to the HEP Conflicts Committee. You are encouraged to carefully read this “Special Factors” section and this entire proxy statement/prospectus, along with the documents incorporated herein by reference.

Effects of the Merger

On August 15, 2023, HF Sinclair, HoldCo, Merger Sub, HEP, the General Partner and HLH entered into the Merger Agreement, pursuant to which Merger Sub will merge with and into HEP, with HEP surviving as an indirect wholly owned subsidiary of HF Sinclair.

As of October 12, 2023, HF Sinclair indirectly owned 59,630,030 HEP Common Units, representing approximately 47% of the issued and outstanding HEP Common Units, through its subsidiaries. HF Sinclair and its subsidiaries also own a non-economic general partner interest and the Special General Partner Interest in HEP. HF Sinclair controls HEP through its indirect ownership of the General Partner, and certain of the executive officers and directors of the General Partner are also officers and/or directors of HF Sinclair (and/or its subsidiaries).

If the Merger is completed, (i) HEP will become an indirect wholly owned subsidiary of HF Sinclair, (ii) the HEP Public Unitholders will no longer have an equity interest in HEP, (iii) the HEP Common Units will no longer be listed on the NYSE, (iv) HEP will commence the suspension and termination of the registration of the HEP Common Units with the SEC, (v) the HEP Common Units owned by HF Sinclair and its subsidiaries immediately prior to the Effective Time will remain outstanding as equity interests in the Surviving Entity, (vi) the non-economic general partner interest will remain outstanding as a non-economic general partner interest in the Surviving Entity and (vii) the Special General Partner Interest will remain outstanding as a general partner interest in the Surviving Entity.

HEP’s net book value (calculated as total assets minus total liabilities) as of June 30, 2023 was approximately $945.6 million, and HEP’s net income attributable to the partners for the fiscal quarter ended June 30, 2023 was

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approximately $50.2 million. As of June 30, 2023, HF Sinclair owned 59,630,030 HEP Common Units, representing an effective beneficial ownership by HF Sinclair of approximately 47% of HEP’s net book value (approximately $444.4 million), as well as an effective beneficial ownership by HF Sinclair attributable to approximately 47% of HEP’s net income attributable to the partners (which 47% interest was approximately $50.6 million for the six months ended June 30, 2023). If the Merger is consummated, HF Sinclair’s aggregate beneficial interest in HEP’s net book value will increase to 100% and net income will increase to 100%. Accordingly, if the Merger is consummated, HF Sinclair’s aggregate beneficial interest in HEP’s net book value will increase to approximately $945.6 million, and net income attributable to the partners will increase to approximately $50.2 million (based on HEP’s June 30, 2023 financial data). HF Sinclair and its Affiliates will also be entitled to any future increase in HEP’s value and all income generated by HEP’s operations going forward.

Background of the Merger

The HF Sinclair Board and HF Sinclair management, which are responsible for overseeing HF Sinclair’s business, as well as the GP Board, regularly review and assess operational and strategic opportunities to increase value for HF Sinclair’s and HEP’s respective investors. In connection with these reviews, these boards of directors and the management team, from time to time, evaluated potential transactions that would further their respective strategic objectives and create value for the HF Sinclair Stockholders and the HEP Unitholders, as applicable. These alternatives included potential acquisitions or business combination transactions with third parties, potential acquisitions or business combination transactions involving HF Sinclair and HEP, and other potential strategic alternatives. In addition, from time to time, HF Sinclair has received and discussed suggestions from several investment banks with respect to, among other things, a possible business combination transaction between HF Sinclair and HEP.

On August 2, 2021, HollyFrontier Corporation, now a wholly owned subsidiary of HF Sinclair (“HFC”), and HEP announced the execution of a Business Combination Agreement and a Contribution Agreement, respectively (the “Sinclair Transaction Agreements”), with The Sinclair Companies (now known as REH Company (“REH”)) and certain other parties thereto, pursuant to which HFC and HEP would acquire Sinclair Oil Corporation and Sinclair Transportation Company LLC, respectively, from REH (the “Sinclair Acquisition”). The execution of the Sinclair Transaction Agreements was preceded by a several year period during which HFC and HEP engaged in intermittent acquisition discussions with REH. Also on August 2, 2021, REH executed a Stockholders Agreement with the predecessor to HF Sinclair and a Unitholders Agreement with HEP.

On March 14, 2022, HFC and HEP consummated the Sinclair Acquisition and announced the establishment of HF Sinclair as the new parent holding company of HFC, HEP and their respective subsidiaries.

In the months following the Sinclair Acquisition, HF Sinclair management analyzed the potential benefits of making HEP a wholly owned subsidiary of HF Sinclair by acquiring the HEP Public Common Units.

On August 31, 2022, the HF Sinclair Board held a regular meeting attended by representatives of HF Sinclair management. During the meeting, representatives of HF Sinclair management reviewed the potential benefits of acquiring the HEP Public Common Units, including the simplification of HF Sinclair’s business and a decrease in costs.

In the months following the HF Sinclair Board meeting on August 31, 2022, HF Sinclair management continued to preliminarily evaluate a potential acquisition of the HEP Public Common Units.

On January 11, 2023, representatives of HF Sinclair management met with representatives of Vinson & Elkins LLP (“Vinson & Elkins”), outside counsel for HF Sinclair. During the meeting, representatives of Vinson & Elkins provided an overview on potential processes for HF Sinclair possibly acquiring the HEP Public Common Units, including timing, structure and governance considerations.

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On February 15, 2023, the HF Sinclair Board held a regular meeting attended by representatives of HF Sinclair management. During the meeting, the HF Sinclair Board reviewed and discussed strategic options for HEP, including a potential acquisition of the HEP Public Common Units.

During the next several months, HF Sinclair management continued to evaluate a potential acquisition of the HEP Public Common Units and began interviewing experienced financial advisors, including Barclays, to advise HF Sinclair on such a transaction. On March 28, 2023, HF Sinclair management notified Barclays that HF Sinclair intended to engage Barclays to advise on the potential transaction, and the parties executed an engagement letter on April 4, 2023. HF Sinclair selected Barclays because of its qualifications, reputation and experience in mergers and acquisitions generally, as well as substantial experience in transactions comparable to the Merger.

Over the course of April 2023, HF Sinclair management, together with Barclays, continued to evaluate a potential acquisition of the HEP Public Common Units, including analyzing different timing and structure considerations.

On April 20, 2023, Mr. Eric Mattson, the Chairperson of the HEP Conflicts Committee, and Mr. Larry Baldwin, the Presiding Director of the GP Board and a member of the HEP Conflicts Committee, were contacted by Mr. Michael Jennings, the then Chief Executive Officer of HF Sinclair. Mr. Jennings informed Mr. Mattson and Mr. Baldwin that HF Sinclair management had been evaluating, as it did periodically, a potential acquisition by HF Sinclair of the HEP Public Common Units. Mr. Jennings also offered to arrange a meeting among Messrs. Mattson, Baldwin and Jennings and Mr. Timothy Go, the incoming Chief Executive Officer and President of HF Sinclair, to further discuss a possible proposal from HF Sinclair to acquire the HEP Public Common Units, noting that although HF Sinclair was not prepared to make a proposal for an acquisition of the HEP Public Common Units, the management of HF Sinclair wanted to make the HEP Conflicts Committee members aware of the possibility of such a proposal.

On April 21, 2023, Mr. Mattson and Mr. Baldwin met with Mr. Jennings and Mr. Go, during which meeting Mr. Go discussed the rationale for a possible proposal from HF Sinclair to acquire the HEP Public Common Units.

On April 24, 2023, Mr. Mattson had a call with Mr. Franklin Myers, Chairperson of the HF Sinclair Board, during which call Mr. Myers reiterated what Mr. Jennings and Mr. Go had told Mr. Mattson and Mr. Baldwin regarding a possible proposal from HF Sinclair with respect to an acquisition of the HEP Public Common Units.

On April 25, 2023, Mr. Mattson and Mr. Baldwin met with Mr. Jennings and Mr. Go, during which meeting Mr. Jennings and Mr. Go discussed potential timing of a proposal from HF Sinclair.

On April 26, 2023, Mr. Go orally informed the full GP Board of a possible proposal from HF Sinclair to acquire the HEP Public Common Units.

On April 28, 2023, the HF Sinclair Conflicts Committee, consisting of Leldon Echols, Craig Knocke and Franklin Myers, held a special informational meeting attended by representatives of HF Sinclair management, Barclays and Vinson & Elkins. The HF Sinclair Board has historically had a standing HF Sinclair Conflicts Committee to evaluate, among other things, transactions between HF Sinclair and HEP. During the meeting, the HF Sinclair Conflicts Committee received presentations from representatives of HF Sinclair management and Barclays regarding a potential acquisition of the HEP Public Common Units.

On May 3, 2023, the HF Sinclair Board held a special meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and Richards, Layton & Finger, P.A. (“RLF”), as Delaware counsel to HF Sinclair. During the meeting, the HF Sinclair Board discussed a potential acquisition of the HEP Public Common Units and received presentations from representatives of HF Sinclair management and Barclays on the potential transaction. A representative of Vinson & Elkins also reviewed with the HF Sinclair Board the directors’ fiduciary duties in the context of evaluating and negotiating a potential transaction. At the meeting, the

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HF Sinclair Board authorized the HF Sinclair Conflicts Committee to review, evaluate, negotiate and determine whether or not to approve, and recommend for approval to the HF Sinclair Board, an acquisition of the HEP Public Common Units. Also during the meeting, the members of the HF Sinclair Conflicts Committee each confirmed their independence with respect to the potential transaction. Following the HF Sinclair Board meeting, the HF Sinclair Conflicts Committee held a meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and RLF. At the meeting, the HF Sinclair Conflicts Committee reviewed and discussed financial analyses prepared by HF Sinclair management and Barclays regarding the potential terms of a proposal. The HF Sinclair Conflicts Committee then authorized HF Sinclair management to deliver a non-binding proposal to the GP Board to acquire all of the HEP Public Common Units (the “Proposed Transaction”), with the proposed consideration for such transaction to be at a fixed exchange ratio of 0.3714 shares of HF Sinclair Common Stock per HEP Public Common Unit, which exchange ratio was derived using the 30-day volume-weighted average price for each security as of market close on May 3, 2023 (the “Initial HF Sinclair Proposal”). Later that day, Mr. Go had a call with Mr. Mattson, during which call Mr. Go informed Mr. Mattson that the HF Sinclair Board had approved the Initial HF Sinclair Proposal. Later that day, Mr. Go delivered to Mr. Mattson a letter from HF Sinclair to the GP Board setting forth the Initial HF Sinclair Proposal.

On May 4, 2023, HF Sinclair and HEP issued separate press releases announcing the submission of the Initial HF Sinclair Proposal by HF Sinclair to the GP Board. Also on May 4, 2023, HF Sinclair filed with the SEC an amendment to its HEP Schedule 13D disclosing the proposal and attaching the non-binding proposal letter as an exhibit.

Following the receipt of the Initial HF Sinclair Proposal, the GP Board authorized the HEP Conflicts Committee to, among other things, review, evaluate and negotiate the Proposed Transaction for the purpose of determining whether to grant Special Approval under the HEP Partnership Agreement.

On May 8, 2023, the HEP Conflicts Committee met with a representative of Morris, Nichols, Arsht & Tunnell LLP (“Morris Nichols”), to approve the engagement of Morris Nichols as special Delaware counsel to the HEP Conflicts Committee with respect to the Proposed Transaction and to discuss, among other things, considerations in connection with the HEP Conflicts Committee’s review and evaluation of the Proposed Transaction. Morris Nichols and the HEP Conflicts Committee executed an engagement letter on May 15, 2023.

On May 10, 2023, the HEP Conflicts Committee met with representatives of Morris Nichols, during which meeting the HEP Conflicts Committee approved the engagement of Gibson, Dunn & Crutcher LLP (“Gibson Dunn”) as its legal counsel with respect to the Proposed Transaction. Gibson Dunn and the HEP Conflicts Committee executed an engagement letter on May 15, 2023.

On May 17, 2023, the GP Board held a special meeting attended by representatives of the General Partner’s management, Gibson Dunn, Morris Nichols, and Bracewell LLP (“Bracewell”), outside counsel for HEP. A representative of Bracewell discussed certain responsibilities of the GP Board related to the Proposed Transaction under the applicable laws of the State of Delaware and the applicable provisions of the HEP Partnership Agreement. During the meeting, the GP Board adopted resolutions that, among other things, (1) determined, pursuant to questionnaires completed by each member of the HEP Conflicts Committee, that (i) each of the members of the HEP Conflicts Committee satisfied the independence and other requirements set forth in the HEP Partnership Agreement to serve as a member of the HEP Conflicts Committee and (ii) none of the members of the HEP Conflicts Committee had any relationship or ownership interest in the General Partner or its affiliates that would interfere with the exercise of such member’s independent judgment in carrying out the responsibilities of a member of the HEP Conflicts Committee in evaluating the Proposed Transaction; (2) authorized, and ratified the prior action of, the HEP Conflicts Committee to review and evaluate the potential conflicts of interest (the “Potential Conflicts”) among or between the General Partner and its affiliates (including HF Sinclair), on the one hand, and HEP, other Group Members (as such term is defined in the First Amended and Restated Limited Liability Company Agreement of the General Partner) and unitholders of HEP, on the other hand, in connection with the Proposed Transaction for the purpose of determining whether to approve, and

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whether to recommend that the GP Board approve, the Proposed Transaction, with such approval and related recommendation constituting “Special Approval” for all purposes under the HEP Partnership Agreement, including Section 7.9(a) thereof; and (3) delegated to the HEP Conflicts Committee the power and authority, consistent with the HEP Conflicts Committee’s charter, to (i) review and evaluate any Potential Conflicts arising in connection with the Proposed Transaction, (ii) negotiate any terms of the Proposed Transaction as it may deem necessary or appropriate, in its sole discretion, (iii) determine whether to approve, and whether to recommend that the GP Board approve, the Proposed Transaction, with such approval and related recommendation constituting “Special Approval” for all purposes under the HEP Partnership Agreement, including Section 7.9(a) thereof, and (iv) make a recommendation to the HEP Unaffiliated Unitholders as to what action, if any, should be taken by the HEP Unaffiliated Unitholders with respect to the Proposed Transaction. The GP Board also authorized and ratified the retention of legal and financial advisors by the HEP Conflicts Committee in its sole discretion.

On May 18, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn to discuss certain issues and considerations in connection with the HEP Conflicts Committee’s review and evaluation of the Proposed Transaction, the transaction process and next steps, including with respect to the selection of a financial advisor to the HEP Conflicts Committee.

On May 18 and 19, 2023, the HEP Conflicts Committee interviewed representatives of three potential financial advisors to advise the HEP Conflicts Committee in connection with the Proposed Transaction, at which interviews representatives of Gibson Dunn and Morris Nichols were in attendance.

On May 19, 2023, the HEP Conflicts Committee met to discuss matters related to the HEP Conflicts Committee’s review and evaluation of the Proposed Transaction and compensation matters. The HEP Conflicts Committee members also discussed the interviews with the potential financial advisors.

On May 22, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn and Morris Nichols. At the meeting, the HEP Conflicts Committee approved the engagement of Intrepid as its financial advisor with respect to the Proposed Transaction because of Intrepid’s knowledge and experience with respect to public mergers and acquisitions and transactions involving master limited partnerships (“MLPs”), its familiarity with HEP and HEP’s business, and its reputation generally and in MLP transactions specifically. The HEP Conflicts Committee and representatives of Gibson Dunn and Morris Nichols also discussed materials prepared by Gibson Dunn and Morris Nichols regarding the framework and process for resolution of conflicts of interest under the HEP Partnership Agreement and Delaware law and compensation matters.

On May 26, 2023, Gibson Dunn, on behalf of the HEP Conflicts Committee and Intrepid, sent a diligence request list to HF Sinclair management. Over the next few weeks, the parties and their respective advisors engaged in a series of diligence calls to discuss items in the diligence request list and other diligence matters.

On June 1, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid, at which meeting Intrepid reviewed certain materials prepared by Intrepid with respect to the Proposed Transaction.

On June 12, 2023, HF Sinclair management held a meeting with members of the HEP Conflicts Committee at the Dallas, Texas office of Vinson & Elkins. Also in attendance were representatives of Barclays, Intrepid, Vinson & Elkins, Gibson Dunn, RLF and Morris Nichols. During the meeting, HF Sinclair management and the General Partner’s management, together with representatives of Barclays, delivered a presentation to the HEP Conflicts Committee regarding the Proposed Transaction. During the presentation, HF Sinclair management and the General Partner’s management discussed the terms proposed by HF Sinclair with respect to the Proposed Transaction, the pro forma structure upon the consummation of the Proposed Transaction, and HF Sinclair’s rationale for the Proposed Transaction. HF Sinclair management and the General Partner’s management also discussed the assets of HF Sinclair and HEP by segment, as well as the financial forecasts of HF Sinclair and HEP, respectively. For more information on the projections prepared by HF Sinclair management, see “—Unaudited Projected Financial Information.” After the meeting with HF Sinclair management and the General

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Partner’s management, the HEP Conflicts Committee, Gibson Dunn and Intrepid had a preliminary discussion regarding the presentation and next steps for the Proposed Transaction.

On June 13, 2023, HF Sinclair granted Gibson Dunn and Intrepid access to a virtual data room containing due diligence materials with respect to HF Sinclair and HEP. From June 2023 until the execution of the Merger Agreement in August 2023, the HEP Conflicts Committee, with the assistance of its advisors, reviewed and discussed various financial and legal matters and information relating to HF Sinclair, HEP and the Proposed Transaction.

On June 14, 2023, HF Sinclair management uploaded a draft merger agreement to the virtual data room for review by the HEP Conflicts Committee and its advisors. The draft merger agreement included, among other things, generally mutual deal protection, termination fee and expense reimbursement obligations of the parties, including a mutual $10.0 million termination fee payable by a party if the merger agreement was terminated due to a change of recommendation in favor of the transaction by such party’s board of directors or conflicts committee.

On June 26, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn and Intrepid, at which meeting Intrepid reviewed the materials prepared by Intrepid with respect to the Proposed Transaction. The participants noted additional data and diligence were needed by Intrepid to conduct further analysis. Subsequently, Intrepid obtained additional data from HF Sinclair management and the General Partner’s management.

On July 13, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid. At the meeting, Intrepid reviewed the materials prepared by Intrepid with respect to the Proposed Transaction, which had been updated based on additional data provided by HF Sinclair management and the General Partner’s management and reflected certain sensitivity analyses performed by Intrepid. The HEP Conflicts Committee requested that Intrepid prepare additional and updated materials for the HEP Conflicts Committee’s review and consideration.

On July 14, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid, at which meeting Intrepid reviewed the materials prepared by Intrepid with respect to the Proposed Transaction, which supplemented the materials provided by Intrepid in connection with the meeting of the HEP Conflicts Committee on July 13, 2023. The participants then discussed a potential counterproposal with respect to the Proposed Transaction. After the discussion, the HEP Conflicts Committee members unanimously agreed to make a counterproposal whereby HF Sinclair would acquire all of the HEP Public Common Units for 0.3714 shares of HF Sinclair Common Stock plus $7.00 in cash for each HEP Public Common Unit (the “First HEP Committee Counterproposal”). The HEP Conflicts Committee members also unanimously agreed that, on behalf of the HEP Conflicts Committee, Gibson Dunn should deliver to HF Sinclair a letter setting forth the First HEP Committee Counterproposal, which Gibson Dunn did later that day.

On July 16, 2023, Barclays called Intrepid and provided initial feedback from HF Sinclair with respect to the First HEP Committee Counterproposal. Later that day, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid to discuss such call, as well as strategy and next steps of the transaction process.

On July 19, 2023, the HF Sinclair Conflicts Committee held a meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and RLF. During the meeting, representatives of HF Sinclair management and Barclays reviewed with the HF Sinclair Conflicts Committee materials regarding the First HEP Committee Counterproposal, including potential options for responding to such counterproposal.

On July 21, 2023, the HF Sinclair Conflicts Committee held a meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and RLF. During the meeting, HF Sinclair management and Barclays reviewed with the HF Sinclair Conflicts Committee additional materials regarding a potential counterproposal in response to the First HEP Committee Counterproposal. Following discussion among the HF Sinclair Conflicts

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Committee and other meeting attendees, the HF Sinclair Conflicts Committee approved a revised non-binding proposal to acquire the HEP Public Common Units for a fixed exchange ratio of 0.315 shares of HF Sinclair Common Stock plus $3.50 in cash for each HEP Public Common Unit (the “Second HF Sinclair Proposal”) and authorized HF Sinclair management to deliver such proposal to the HEP Conflicts Committee. Later that day, Mr. Go delivered a letter setting forth the Second HF Sinclair Proposal to the HEP Conflicts Committee.

On July 24, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid to discuss the Second HF Sinclair Proposal. At the meeting, Intrepid reviewed the updated financial analyses prepared by Intrepid with respect to the Proposed Transaction. The participants also discussed negotiation strategy, the upcoming GP Board meeting and next steps.

On July 26, 2023, after a regularly scheduled GP Board meeting, Mr. Mattson and Mr. Baldwin, pursuant to Mr. Go’s request, met briefly with Mr. Go and Mr. Jennings to discuss the process for the Proposed Transaction.

On July 27, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid, during which meeting (i) the participants discussed the meeting Mr. Mattson and Mr. Baldwin had with Mr. Go and Mr. Jennings on the previous day; (ii) Intrepid reviewed the updated financial analyses prepared by Intrepid based on the latest market data; and (iii) Gibson Dunn provided an overview of the draft merger agreement provided by HF Sinclair in connection with the Proposed Transaction and a detailed summary of the proposed changes made by Gibson Dunn and Morris Nichols in a revised draft of the merger agreement. Discussion ensued among the participants regarding a potential counterproposal to HF Sinclair with respect to the Proposed Transaction. After such discussion, the HEP Conflicts Committee members unanimously: (i) authorized a counterproposal whereby HF Sinclair would acquire all of the HEP Public Common Units at a fixed exchange ratio of 0.3714 shares of HF Sinclair Common Stock plus $4.00 in cash per HEP Public Common Unit, which counterproposal would be delivered by a letter to HF Sinclair (the “Second HEP Committee Counterproposal”); (ii) confirmed agreement with the proposed changes to the draft merger agreement discussed at the meeting; (iii) directed Gibson Dunn to further revise the draft merger agreement to incorporate comments from the HEP Conflicts Committee; and (iv) directed Gibson Dunn to, on behalf of the HEP Conflicts Committee, send the Second HEP Committee Counterproposal and the markup of the draft merger agreement to HF Sinclair and its legal counsel following approval by the HEP Conflicts Committee.

On July 28, 2023, upon the HEP Conflicts Committee’s approval, Gibson Dunn delivered the letter setting forth the Second HEP Committee Counterproposal and a markup of the draft merger agreement to HF Sinclair and its legal counsel on behalf of the HEP Conflicts Committee. The revised merger agreement, among other things, (i) modified and deleted certain representations and warranties of HEP; (ii) deleted various interim operating covenants with respect to HEP and added certain interim operating covenants with respect to HF Sinclair; (iii) limited the circumstances under which the HF Sinclair Board or the HF Sinclair Conflicts Committee could change its respective recommendation to HF Sinclair Stockholders; (iv) added an affirmative obligation of HEP to continue to make quarterly distributions no less than $0.35 per HEP Common Unit through the closing of the Proposed Transaction consistent with past practice; (v) required HF Sinclair to reimburse HEP for expenses up to $5.0 million for failure to obtain the HF Sinclair Stockholder Approval; (vi) increased the termination fee payable to HEP by HF Sinclair from $10.0 million to 3% of the transaction value, which based on the Second HEP Committee Counterproposal, would have equaled approximately $40 million; and (vii) modified certain closing conditions regarding representations and warranties to increase closing certainty.

On August 1, 2023, the HF Sinclair Conflicts Committee held a meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and RLF. During the meeting, representatives of HF Sinclair management and Barclays presented certain updated financial analyses related to the Second HEP Committee Counterproposal. Representatives of Vinson & Elkins also provided an overview of the key issues in Gibson Dunn’s markup of the merger agreement. Later that day, Barclays called and relayed to Intrepid, on behalf of HF Sinclair, that (i) the consideration proposed by the Second HEP Committee Counterproposal was well above what HF Sinclair was willing to accept and (ii) HF Sinclair confirmed its prior proposal of 0.315 shares of HF

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Sinclair Common Stock and $3.50 in cash in exchange for each HEP Public Common Unit and would pause in formally responding to the Second HEP Committee Counterproposal.

On August 2, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid to discuss a call between Barclays and Intrepid on the previous day and a potential response to HF Sinclair. Representatives of Intrepid referenced the updated financial analyses of the Proposed Transaction prepared by Intrepid based on the latest market data, and provided observations and suggestions. Discussion ensued among the HEP Conflicts Committee members, Intrepid, Gibson Dunn and Morris Nichols regarding the financial analyses, a potential response to HF Sinclair, negotiation strategy and next steps. After such discussion, the HEP Conflicts Committee members unanimously authorized Intrepid to, on behalf of the HEP Conflicts Committee, inform Barclays that the HEP Conflicts Committee would potentially consider a proposal from HF Sinclair with respect to the Proposed Transaction within the range of the Second HF Sinclair Proposal and the Second HEP Committee Counterproposal, which representatives of Intrepid did later that day.

Over the next several days, representatives of HF Sinclair management, Barclays and Vinson & Elkins held several calls to discuss potential counterproposals to the HEP Conflicts Committee. During this period, Mr. Go also communicated with members of the HF Sinclair Conflicts Committee regarding potential counterproposals.

On August 8, 2023, at the direction of HF Sinclair management, Barclays called and relayed to Intrepid that (i) HF Sinclair could potentially make a proposal of 0.315 shares of HF Sinclair Common Stock and $3.75 in cash in exchange for each HEP Public Common Unit; and (ii) if an agreement could not be reached by the HEP Conflicts Committee and HF Sinclair in the near term, then HF Sinclair would pause on the Proposed Transaction process.

On August 9, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid to discuss the call between Barclays and Intrepid on the previous day and a potential response to HF Sinclair. Discussion ensued among the HEP Conflicts Committee members, Intrepid, Gibson Dunn and Morris Nichols regarding a potential response to HF Sinclair, negotiation strategy and next steps of the transaction process. Representatives of Intrepid referenced the updated financial analyses of the Proposed Transaction prepared by Intrepid based on the latest market data, and provided observations and suggestions. After such discussion, the HEP Conflicts Committee members unanimously authorized Intrepid to, on behalf of the HEP Conflicts Committee, inform Barclays that the HEP Conflicts Committee could potentially agree to a Proposed Transaction whereby the consideration would be 0.315 shares of HF Sinclair Common Stock and $4.00 in cash in exchange for each HEP Public Common Unit if HF Sinclair were to make such a proposal. Representatives of Intrepid informed Barclays as such later that day.

On August 10, 2023, Barclays called and relayed to Intrepid, on behalf of HF Sinclair, that HF Sinclair would propose to the HF Sinclair Conflicts Committee that HF Sinclair make a proposal to acquire all the HEP Public Common Units for 0.315 shares of HF Sinclair Common Stock and $4.00 in cash per HEP Public Common Unit as HF Sinclair’s best and final proposal (the “Best and Final HF Sinclair Proposal”).

Later that day, Gibson Dunn received a further revised draft merger agreement from Vinson & Elkins, which, among other things: (i) reinserted certain representations and warranties of HEP; (ii) reinserted certain interim operating covenants with respect to HEP and deleted certain interim operating covenants with respect to HF Sinclair; (iii) rejected the limitation on the circumstances under which the HF Sinclair Board or the HF Sinclair Conflicts Committee could change its respective recommendation to HF Sinclair Stockholders; (iv) accepted the obligation of HEP to continue to make quarterly distributions no less than $0.35 per HEP Common Unit through the closing of the Proposed Transaction consistent with past practice; (v) rejected the requirement for HF Sinclair to reimburse HEP for expenses up to $5.0 million for failure to obtain HF Sinclair Stockholder Approval; (vi) rejected the increase of the termination fee payable to HEP by HF Sinclair from $10.0 million to 3% of the transaction value; and (vii) rejected certain modifications to closing conditions regarding representations and warranties.

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On August 11, 2023, the HF Sinclair Conflicts Committee held a meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and RLF. During the meeting, representatives of HF Sinclair management and Barclays presented certain updated materials related to the Best and Final Sinclair Proposal and Barclays updated the HF Sinclair Conflicts Committee on Barclays’ discussions with Intrepid. Following discussion among the HF Sinclair Conflicts Committee and other meeting attendees, the HF Sinclair Conflicts Committee formally approved the Best and Final HF Sinclair Proposal and authorized HF Sinclair management to deliver such proposal to the HEP Conflicts Committee noting that the proposal was the HF Sinclair Conflicts Committee’s best and final offer. Later that day, Mr. Go delivered a letter setting forth the Best and Final HF Sinclair Proposal to the HEP Conflicts Committee, noting, among other things, HF Sinclair’s views on (1) the compelling benefits of the transaction to holders of the HEP Public Common Units, including the meaningful premium to the historical trading price of the HEP Common Units prior to the announcement of HF Sinclair’s initial proposal, an investment in a larger, more diversified entity with substantially higher trading liquidity and (2) the meaningful headwinds HEP would face under the status quo, including HF Sinclair’s views on HEP’s limited growth opportunities in part due to MLPs’ higher cost of capital and diminished access to equity capital markets, the need for HEP to focus on reducing its leverage rather than on distribution growth and the lack of desire by HF Sinclair to enter into additional long-term agreements with high-volume commitments.

Also on August 11, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid to discuss the Best and Final HF Sinclair Proposal, the potential tax impacts of the Proposed Transaction on the holders of the HEP Public Common Units, the status of the transaction documentation and next steps. Representatives of Intrepid also referenced the updated financial analyses prepared by Intrepid based on the latest market data and provided observations. After such discussion, the HEP Conflicts Committee members unanimously agreed that Mr. Mattson should contact representatives of HF Sinclair and Intrepid should contact Barclays, in each case, on behalf of the HEP Conflicts Committee, to acknowledge the agreement on the consideration for the Proposed Transaction, subject to agreement on definitive documentation. Representatives of Intrepid informed Barclays as such later that day. Mr. Mattson contacted Mr. Go and indicated the same on August 12, 2023.

Between August 11, 2023 and August 14, 2023, Gibson Dunn and Vinson & Elkins exchanged several markups of the draft merger agreement. During such period, the HEP Conflicts Committee members were informed of the proposed revisions to the draft merger agreement and provided feedback to Gibson Dunn and Morris Nichols. On August 13, 2023, Gibson Dunn, Morris Nichols, Vinson & Elkins, RLF and representatives of HF Sinclair management and the General Partner’s management had a call regarding the open issues in the draft merger agreement. On August 14, 2023, Gibson Dunn and Vinson & Elkins had multiple calls and email exchanges to negotiate and finalize the terms of the merger agreement and the parties’ respective disclosure schedules. On August 14, 2023, Gibson Dunn sent Vinson & Elkins the proposed execution version of the merger agreement, subject to final approval by the HEP Conflicts Committee. Among other things, the proposed execution version of the merger agreement: (i) reflected compromises by the HEP Conflicts Committee and HF Sinclair with respect to the representations and warranties and interim operating covenants of HEP and HF Sinclair; (ii) limited the circumstances under which the HF Sinclair Board or the HF Sinclair Conflicts Committee could change its respective recommendation to HF Sinclair Stockholders; (iii) required HF Sinclair to reimburse HEP for expenses up to $5.0 million for failure to obtain the HF Sinclair Stockholder Approval; and (iv) set the termination fee payable to HEP by HF Sinclair at $20.0 million. Later that day, HF Sinclair management and the General Partner’s management sent to Gibson Dunn and Vinson & Elkins the proposed final disclosure schedules of HEP and HF Sinclair.

On August 14, 2023, the HF Sinclair Board held a special meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and RLF. During the meeting, representatives of HF Sinclair management and Barclays reviewed with the HF Sinclair Board certain updated financial analyses related to the proposed transaction. In addition, Mr. Echols, chairperson of the HF Sinclair Conflicts Committee, reviewed with the HF Sinclair Board the process the HF Sinclair Conflicts Committee had undertaken in evaluating the proposed transaction. A representative of Vinson & Elkins also reviewed with the HF Sinclair Board a summary of the merger agreement.

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On the morning of August 15, 2023, the HF Sinclair Conflicts Committee held a meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and RLF. During the meeting, representatives of HF Sinclair and Barclays reviewed the final terms of the transaction, including the final consideration amount of a fixed exchange ratio of 0.315 shares of HF Sinclair Common Stock plus $4.00 in cash for each HEP Public Common Unit. In addition, a representative of Vinson & Elkins reviewed the proposed final terms of the Merger Agreement. Following discussion, the HF Sinclair Conflicts Committee unanimously (i) determined that the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, are advisable and in the best interests of HF Sinclair and the HF Sinclair Stockholders, (ii) approved the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, (iii) recommended that the HF Sinclair Board approve the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, and (iv) resolved and recommended that the HF Sinclair Board resolve, to (a) direct that the HF Sinclair Stock Issuance be submitted to a vote of the HF Sinclair Stockholders for approval at the HF Sinclair Special Meeting and (b) recommend approval of the HF Sinclair Stock Issuance by the HF Sinclair Stockholders at the HF Sinclair Special Meeting. Following the HF Sinclair Conflicts Committee meeting, the HF Sinclair Board held a special meeting attended by representatives of HF Sinclair management, Barclays, Vinson & Elkins and RLF. During the meeting, the Chairperson of the HF Sinclair Conflicts Committee reported on the determinations and approvals made by the HF Sinclair Conflicts Committee members and representatives of HF Sinclair and Barclays reviewed the final terms of the transaction, including the final consideration amount of a fixed exchange ratio of 0.315 shares of HF Sinclair Common Stock plus $4.00 in cash for each HEP Public Common Unit. In addition, a representative of Vinson & Elkins reviewed the proposed final terms of the Merger Agreement. Following discussion, the HF Sinclair Board (acting, in part, based upon the recommendation of the HF Sinclair Conflicts Committee) unanimously (i) determined that the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, are in the best interests of HF Sinclair and the HF Sinclair Stockholders, (ii) approved the Merger Agreement and the Transactions, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, (iii) directed that the HF Sinclair Stock Issuance be submitted to a vote of the HF Sinclair Stockholders for approval at the HF Sinclair Special Meeting and (iv) resolved to recommend approval of the HF Sinclair Stock Issuance by the HF Sinclair Stockholders at the HF Sinclair Special Meeting.

Also on August 15, 2023, the HEP Conflicts Committee met with representatives of Gibson Dunn, Morris Nichols and Intrepid. Gibson Dunn discussed the summary of the proposed execution version of the Merger Agreement prepared by Gibson Dunn. Representatives of Intrepid then discussed materials prepared by Intrepid regarding financial analyses with respect to the Proposed Transaction and delivered an oral opinion, confirmed by delivery of a written opinion dated August 15, 2023, to the HEP Conflicts Committee to the effect that, as of such date and based upon and subject to the assumptions, procedures, factors, qualifications, limitations and other matters set forth in Intrepid’s written opinion, the Merger Consideration is fair, from a financial point of view, to the HEP Unaffiliated Unitholders. After all representatives of Intrepid left the meeting, Morris Nichols reviewed duties of the HEP Conflicts Committee under the HEP Partnership Agreement, and Gibson Dunn reviewed Gibson Dunn’s observations on the HEP Conflicts Committee’s process. Thereafter, the HEP Conflicts Committee, by unanimous vote, in good faith (a) determined that the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, are in the best interests of HEP, including the HEP Unaffiliated Unitholders, (b) approved the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger (the foregoing constituting “Special Approval” for all purposes of the HEP Partnership Agreement, including Section 7.9(a) thereof) on the terms and subject to the conditions set forth in the Merger Agreement, (c) recommended to the GP Board the approval by the GP Board of the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, on the terms and subject to the conditions set forth in the Merger Agreement, and (d) resolved, and recommended that the GP Board resolve, to (i) direct that the Merger Agreement and the Merger be submitted to a vote of the HEP Unitholders for approval pursuant to Section 14.3 of the HEP Partnership Agreement and (ii) recommend approval of the Merger Agreement and the Merger by the HEP Unitholders at the HEP Special Meeting. Following the HEP Conflicts Committee meeting, the GP Board held a special meeting attended by

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representatives of HEP management and Bracewell, during which the Chairperson of the HEP Conflicts Committee provided the GP Board with a report on the process conducted by the HEP Conflicts Committee in its evaluation of the proposed Merger, including (i) the HEP Conflicts Committee’s consideration of the merits of the proposed Merger over the course of a number of meetings, including meetings with its financial and legal advisors, (ii) the HEP Conflicts Committee’s negotiation of the terms of the Merger Agreement, including the consideration to be received by the HEP Unaffiliated Unitholders, (iii) the receipt of the opinion of Intrepid, as described above, and (iv) the determination, approval and recommendations of the HEP Conflicts Committee with respect to the Merger Agreement and the Merger, as described above. Following such report and acting upon the recommendation of the HEP Conflicts Committee, the GP Board unanimously (a) determined that the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, are in the best interests of HEP, including the HEP Unaffiliated Unitholders, (b) approved the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger, on the terms and subject to the conditions set forth in the Merger Agreement, and (c) resolved to (1) direct that the Merger Agreement and the Merger be submitted to a vote of the HEP Unitholders for approval pursuant to Section 14.3 of the HEP Partnership Agreement and (2) recommend the approval of the Merger Agreement and the Merger by the HEP Unitholders at the HEP Special Meeting.

Later in the afternoon on August 15, 2023, following the closing of trading on the NYSE, the parties exchanged an executed final version of the Merger Agreement and the final versions of the disclosure schedules.

Before the opening of trading on the NYSE on August 16, 2023, HF Sinclair and HEP issued a joint press release announcing the execution of the Merger Agreement and HF Sinclair and HEP each filed with the SEC Current Reports on Form 8-K attaching a copy of the joint press release as an exhibit. Later that day, HF Sinclair and HEP each filed with the SEC Current Reports on Form 8-K attaching a copy of the Merger Agreement and letter to their respective employees as exhibits. HF Sinclair also filed an amendment to its HEP Schedule 13D disclosing the execution of the Merger Agreement.

Resolution of Conflicts of Interest; Standards of Conduct and Modification of Duties

The approval of the Merger Agreement and the transactions contemplated thereby, including the Merger, by a majority of the members of the HEP Conflicts Committee constitutes “Special Approval” under the HEP Partnership Agreement. Under Section 7.9 of the HEP Partnership Agreement, whenever a potential conflict of interest exists or arises between the General Partner or any of its Affiliates, on the one hand, and HEP, any Group Member, any Partner or any Assignee, on the other, any resolution or course of action by the General Partner or its Affiliates in respect of such conflict of interest shall be permitted and deemed approved by all Partners, and shall not constitute a breach of the HEP Partnership Agreement, of any Group Member Agreement (as defined in the HEP Partnership Agreement), or of any agreement contemplated therein, or of any duty stated or implied by law or equity, if the resolution or course of action in respect of such conflict of interest is (i) approved by Special Approval, (ii) approved by the vote of a majority of the HEP Common Units (excluding HEP Common Units owned by the General Partner and its Affiliates), (iii) on terms no less favorable to HEP than those generally being provided to or available from unrelated third parties or (iv) fair and reasonable to HEP, taking into account the totality of the relationships between the parties involved (including other transactions that may be particularly favorable or advantageous to HEP).

Section 7.10(b) of the HEP Partnership Agreement provides that any action taken or omitted to be taken by the General Partner in reliance upon the opinion of an investment banker, among others, as to matters reasonably believed by the General Partner to be in such person’s professional or expert competence shall be conclusively presumed to have been done or omitted in good faith and in accordance with such opinion.

Position of HF Sinclair, HoldCo and Merger Sub as to the Fairness of the Merger

Under the rules governing “going private” transactions, including Rule 13e-3 under the Exchange Act, each of the Parent Entities is deemed to be engaged in a “going private” transaction with respect to HEP and the Merger

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and, therefore, is required to express its belief as to the fairness of the Merger to the HEP Unaffiliated Unitholders pursuant to Rule 13e-3 under the Exchange Act and the related rules under the Exchange Act. Each of the Parent Entities is making the statements included in this section solely for the purposes of complying with the requirements of Rule 13e-3 and related rules under the Exchange Act. The views of each of the Parent Entities as to the fairness of the Merger (which is the Rule 13e-3 transaction for which a Schedule 13E-3 will be filed with the SEC at the same time as this joint proxy statement/prospectus) should not be construed as a recommendation to any HEP Unaffiliated Unitholder as to how such HEP Unaffiliated Unitholder should vote on the Merger Proposal.

None of the Parent Entities participated in the deliberations of the HEP Conflicts Committee regarding, or received advice from the HEP Conflicts Committee’s legal or financial advisors as to, the fairness of the Merger. None of the Parent Entities has performed, or engaged a financial advisor to perform, any valuation or other analysis for the purpose of assessing the fairness of the Merger to the HEP Unaffiliated Unitholders. The Parent Entities believe that the interests of the HEP Unaffiliated Unitholders were represented by the HEP Conflicts Committee, which negotiated the terms and conditions of the Merger Agreement and the transactions contemplated thereby, including the Merger, with the assistance of independent legal and financial advisors.

However, based on (i) the requirement of HEP Unitholder Approval, (ii) the review and approval of the Merger Agreement and the Transactions, including the Merger, by the HF Sinclair Conflicts Committee as a related party transaction pursuant to HF Sinclair’s Related Party Transaction Policy, (iii) the review and approval of the Merger Agreement and the transactions contemplated thereby, including the Merger, by the HEP Conflicts Committee, (iv) the Parent Entities’ knowledge and analysis of available information relating to HF Sinclair, HEP and the General Partner, (v) the factors considered by, and findings of, the HEP Conflicts Committee and the GP Board discussed in the section entitled “—Recommendations of the HEP Conflicts Committee and the GP Board and the Reasons for their Recommendations,” beginning on page 56, which analyses as set forth in this joint proxy statement/prospectus the Parent Entities expressly adopted in making their determination of fairness, which the Parent Entities considered material and are not listed in any relative order of importance, and (vi) the factors set forth below in the section entitled “—Recommendations of the HF Sinclair Conflicts Committee and the HF Sinclair Board and their Reasons for the Merger,” which are considered material and are not listed in any relative order of importance, solely for the purpose of complying with the requirements of Rule 13e-3 and the related rules under the Exchange Act, the Parent Entities believe that the Merger is both substantively and procedurally fair to the HEP Unaffiliated Unitholders.

The foregoing discussion of the information and factors considered and given weight by HF Sinclair, acting on its own behalf and on behalf of HoldCo and Merger Sub, is not intended to be exhaustive, but includes the factors considered by the Parent Entities that each believes to be material to the fairness determination regarding the fairness of the Merger for the purpose of complying with the requirements of Rule 13e-3 and the related rules under the Exchange Act. The Parent Entities did not find it practicable to, and did not, quantify or otherwise attach relative weights to the foregoing factors in reaching their position as to the fairness of the Merger. Rather, HF Sinclair, acting on its own behalf and on behalf of HoldCo and Merger Sub, made its fairness determination after considering all of the factors as a whole. In making its determination, the Parent Entities expressly adopted the analyses of the HEP Conflicts Committee and the GP Board. HF Sinclair management did not consider, and did not provide for consideration of the HF Sinclair Board, the net book value of HEP, which is an accounting concept, for purposes of making its recommendation, because, it believes net book value is indicative of neither HEP’s market value nor its value as a going concern, but rather is an indicator of historical costs. HF Sinclair management did not consider, and did not provide for consideration of the HF Sinclair Board, the liquidation value of HEP because HEP was viewed to be a viable, going concern and therefore liquidation value was not a relevant methodology.

Recommendations of the HF Sinclair Conflicts Committee and the HF Sinclair Board and their Reasons for the Merger

The HF Sinclair Conflicts Committee consists of three independent directors of the HF Sinclair Board who do not have any ownership or other interest in HEP: Leldon E. Echols, R. Craig Knocke and Franklin Myers. The HF Sinclair Board authorized the HF Sinclair Conflicts Committee to (i) review and evaluate the terms and

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conditions of the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance, on behalf of HF Sinclair and the HF Sinclair Stockholders; (ii) negotiate, or delegate (subject to continued oversight by the HF Sinclair Conflicts Committee) to any person or persons the ability to negotiate, the terms and conditions of the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance; (iii) determine whether to approve and recommend for approval to the HF Sinclair Board the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance; and (iv) determine whether the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance, are advisable and fair and reasonable to, and in the best interests of, HF Sinclair and the HF Sinclair Stockholders.

The HF Sinclair Conflicts Committee consulted with and received advice from Vinson & Elkins and RLF as legal counsel and Barclays as financial advisor in connection with its evaluation of the proposed transaction. The HF Sinclair Conflicts Committee, among other things, conducted a review and evaluation of the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance, reviewed the Merger Agreement and directed negotiations with the HEP Conflicts Committee and its representatives with respect to the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance.

On August 15, 2023, the HF Sinclair Conflicts Committee, by unanimous vote, (i) determined that the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance, are advisable and in the best interests of HF Sinclair and the HF Sinclair Stockholders, (ii) approved the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, (iii) recommended to the HF Sinclair Board the approval by the HF Sinclair Board of the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, and (iv) resolved, and recommended that the HF Sinclair Board resolve, to (a) direct that the HF Sinclair Stock Issuance be submitted to a vote of the HF Sinclair Stockholders for approval at a special meeting of the HF Sinclair Stockholders, and (b) recommend approval of the HF Sinclair Stock Issuance by the HF Sinclair Stockholders at the HF Sinclair Special Meeting.

Later on August 15, 2023, the HF Sinclair Board (acting, in part, based upon the receipt of such approval and recommendation of the HF Sinclair Conflicts Committee), by unanimous vote, (i) determined that the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance, are advisable and in the best interests of HF Sinclair and the HF Sinclair Stockholders, (ii) approved the Merger Agreement and the transactions contemplated by the Merger Agreement, including the Merger and the HF Sinclair Stock Issuance, on the terms and subject to the conditions set forth in the Merger Agreement, (iii) directed that the HF Sinclair Stock Issuance be submitted to a vote of the HF Sinclair Stockholders for approval at the HF Sinclair Special Meeting and (iv) resolved to recommend approval of the HF Sinclair Stock Issuance by the HF Sinclair Stockholders at the HF Sinclair Special Meeting.

The HF Sinclair Conflicts Committee considered various factors in making its determination and approvals and the related recommendation to the HF Sinclair Board.

In addition to considering the terms and conditions of the Merger Agreement, the HF Sinclair Conflicts Committee consulted with financial and legal advisors and considered the following factors as generally favorable with respect to the Merger and the transactions related thereto, including the HF Sinclair Stock Issuance:

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The HF Sinclair Conflicts Committee viewed the following factors as generally negative or unfavorable in making a determination with respect to the Merger and the transactions related thereto, including the HF Sinclair Stock Issuance:

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The foregoing discussion of the information and factors considered by the HF Sinclair Conflicts Committee is not intended to be exhaustive, but includes material factors the HF Sinclair Conflicts Committee considered. In view of the variety of factors and the quality and amount of information considered, the HF Sinclair Conflicts Committee as a whole did not find it practicable to and did not quantify or otherwise assign relative weights to the specific factors considered in reaching its determination but conducted an overall evaluation of the Merger. Individual members of the HF Sinclair Conflicts Committee may have given different relative considerations to different factors. After taking into account all of the factors set forth above, as well as others, the HF Sinclair Conflicts Committee concluded that the potential benefits of the Merger and the transactions related thereto, including the HF Sinclair Stock Issuance, outweighed any negative or unfavorable considerations.

The explanation of the reasoning of the HF Sinclair Conflicts Committee and certain information presented in this section are forward-looking in nature and, therefore, the information should be read in light of the factors discussed in the sections entitled “Cautionary Statement Regarding Forward-Looking Statements” and “Risk Factors.”

In reaching its conclusions regarding the Merger, the HF Sinclair Board considered all matters and factors it believed were necessary or appropriate to enable it to reach an informed decision, including the process by which the HF Sinclair Conflicts Committee made its recommendations, the matters described above or considered by the HF Sinclair Conflicts Committee, and the HF Sinclair Board’s understanding of the process conducted by the HEP Conflicts Committee. As in the case of the HF Sinclair Conflicts Committee, in view of the variety of factors and the quality and amount of information considered, the HF Sinclair Board as a whole did not find it practicable to and did not quantify or otherwise assign relative weights to, the specific factors considered in reaching its determination. Individual members of the HF Sinclair Board may have given different relative considerations to different factors.

Purpose and Reasons of the Parent Entities for the Merger

Under the SEC rules governing “going-private” transactions, including Rule 13e-3 under the Exchange Act, each of the Parent Entities is deemed to be engaged in a “going-private” transaction with respect to HEP and the Merger and, therefore, is required to express its purposes and reasons for the Merger to the HEP Unaffiliated Unitholders. The Parent Entities are making the statements included in this section solely for the purpose of complying with the requirements of Rule 13e-3 and related rules under the Exchange Act.

The Parent Entities’ purpose of the Merger is for HF Sinclair to acquire all of the HEP Public Common Units, with the result that HF Sinclair will indirectly own 100% of the HEP Common Units and will bear the rewards and risks of such ownership after the HEP Common Units cease to be publicly traded.

The Parent Entities have undertaken to pursue the Merger at this time, as opposed to any previous time, for the reasons described in the section titled “—Recommendations of the HF Sinclair Conflicts Committee and the HF Sinclair Board and their Reasons for the Merger.”

Although the Parent Entities believe that there will be opportunities associated with their investment in HEP, the Parent Entities realize that there are also risks (including the risks and uncertainties relating to the prospects of HEP) and that such opportunities may never be fully realized. Further, following the Merger, there will be no trading market for the HEP Common Units.

The Parent Entities believe that structuring the proposed Merger as a merger transaction is preferable to other transaction structures because it provides a prompt and orderly transfer of ownership of the HEP Public Common

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Units in a single step, without the necessity of additional HEP Public Common Unit purchases by HF Sinclair, either through a tender offer, individually negotiated purchases or open market purchases, and without incurring additional transaction costs associated with such activities. Further, the Merger provides an opportunity for the HEP Unaffiliated Unitholders to receive a premium for their HEP Common Units.

Recommendations of the HEP Conflicts Committee and the GP Board and the Reasons for their Recommendations

In evaluating the Proposed Transaction and reaching its determination and approval of the Merger Agreement and the transactions contemplated thereby, the HEP Conflicts Committee considered information supplied by HF Sinclair management and the General Partner’s management, HF Sinclair and its affiliates, consulted with its legal and financial advisors, and considered a number of factors. The HEP Conflicts Committee also consulted with its legal counsel regarding its authority and duties.

The HEP Conflicts Committee considered the following factors to be generally positive or favorable in making its determination and granting “Special Approval” of the Proposed Transaction:

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As part of its deliberative process, the HEP Conflicts Committee considered the following factors to be generally negative or unfavorable in making its determination and granting “Special Approval” of the Proposed Transaction:

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The HEP Conflicts Committee also considered the following factors relating to the procedural safeguards that the HEP Conflicts Committee believed were and are present with respect to the fairness of the Proposed Transaction and to permit the HEP Conflicts Committee to make its determination and grant “Special Approval”, which the HEP Conflicts Committee believes support its decision and provide assurance as to the procedural fairness of the Proposed Transaction to the HEP Unaffiliated Unitholders:

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After taking into account all of the factors set forth above, as well as others, the HEP Conflicts Committee concluded that the potential benefits of the Proposed Transaction outweighed any negative or unfavorable considerations and determined that the Merger Agreement and the transactions contemplated thereby, including the Merger, are in the best interests of HEP, including the HEP Unaffiliated Unitholders.

The foregoing discussion of the information and factors considered by the HEP Conflicts Committee is not intended to be exhaustive, but includes material factors the HEP Conflicts Committee considered. In view of the variety of factors considered in connection with its evaluation of the Proposed Transaction and the complexity of these matters, the HEP Conflicts Committee did not find it useful and did not attempt to quantify or assign any relative or specific weights to the various factors considered in making its determination and granting its approval. In addition, each of the members of the HEP Conflicts Committee may have given differing weights to different factors. The HEP Conflicts Committee granted its approval based on the totality of information presented to, and the investigation conducted by, the HEP Conflicts Committee. It should be noted that certain statements and other information presented in this section are forward-looking in nature and, therefore, should be read in the light of the factors discussed under the heading “Cautionary Statement Regarding Forward-Looking Statements.”

The GP Board considered the following factors, the order of which does not necessarily reflect their relative significance, in making its determinations and approvals of the Merger Agreement and the transactions contemplated thereby:

The foregoing discussion of the information and factors considered by the GP Board is not intended to be exhaustive, but includes the factors believed by the GP Board to be material to its determinations and approvals. In view of the variety of factors considered in connection with its evaluation of the Merger and the complexity of these matters, the GP Board did not find it practicable to, and did not, quantify or otherwise attach relative weights to the foregoing factors in making its determinations and approvals. Individual members of the GP Board may have given different relative considerations to different factors. The GP Board made its determinations and approvals based upon the totality of the information presented to and considered by the GP

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Board in making its determinations and approvals. In making its determinations and approvals, the GP Board expressly adopted the analysis of the HEP Conflicts Committee, which is discussed above, which in turn expressly adopted the analyses and opinion of Intrepid, among other factors considered, in the course of reaching the HEP Conflicts Committee’s decision to recommend that the GP Board approve the Merger Agreement and the transactions contemplated thereby.

In addition, under the rules governing “going private” transactions, including Rule 13e-3 under the Exchange Act, each of HEP, HLH and the General Partner is deemed to be engaged in a “going private” transaction with respect to the Merger and, therefore, is required to express its belief as to the fairness of the Merger to the HEP Unaffiliated Unitholders pursuant to Rule 13e-3 under the Exchange Act. The GP Board, on behalf of HEP, HLH and the General Partner, is making the following statements for the purposes of complying with the requirements of Rule 13e-3 and related rules under the Exchange Act. The GP Board, on behalf of HEP, HLH and the General Partner, on the basis of the factors described above, believes the Merger (which is the Rule 13e-3 transaction for which a Schedule 13E-3 Transaction Statement was filed with the SEC) is both procedurally and substantively fair to the HEP Unaffiliated Unitholders.

Other than its review and adoption of the analysis of the HEP Conflicts Committee, the GP Board did not conduct a going-concern valuation of HEP in evaluating the Merger because of its belief that the financial analyses presented by Intrepid to the HEP Conflicts Committee, as more fully summarized in the section entitled “Opinion of the Financial Advisor to the HEP Conflicts Committee,” represented potential valuations of HEP as it continues to operate its business as a going concern. The GP Board did not find it practicable to, and did not, quantify or otherwise attach relative weights to the foregoing factors in reaching its position as to the fairness of the Merger. Rather, the GP Board, on behalf of HEP, HLH and the General Partner made its fairness determination after considering all of the factors as a whole. The GP Board did not consider the net book value of HEP, which is an accounting concept, for purposes of making its recommendation, because, it believed net book value is indicative of neither HEP’s market value nor its value as a going concern, but rather is an indicator of historical costs. In the course of reaching its decision to recommend to the HEP Unitholders that they approve the Merger Agreement and the transactions contemplated thereby, including the Merger, the GP Board did not consider the liquidation value of HEP because it considered HEP to be a viable, going concern and therefore did not consider liquidation value to be a relevant methodology. Furthermore, the GP Board did not consider the prices paid in the purchases described in the section entitled “Comparative Market Prices and Cash Dividend/Distribution Information—Prior Stock Purchases” because such purchases were made at then-current trading prices for HEP Common Units and the GP Board believed that such prices were not indicative of HEP’s current market value. In addition, the GP Board was not aware of, and did not consider, any firm offer made by any unaffiliated person during the past two years for (i) a merger or consolidation of HEP with another company; (ii) the sale or transfer of all or substantially all of HEP’s assets; or (iii) the purchase of securities of HEP that would enable such person to exert control of or significant influence over HEP.

The GP Board concluded that approval by a majority of the HEP Unaffiliated Unitholders is not necessary for approval of the Merger as such approval is not required under Delaware law, and the GP Board believes the various procedural safeguards that have been adopted, as described above, have ensured the procedural fairness of the Merger.

The HEP Conflicts Committee and the GP Board unanimously recommend that HEP Unitholders vote “FOR” the Merger Proposal. The GP Board unanimously recommends that HEP Unitholders vote “FOR” the HEP Adjournment Proposal.

Unaudited Projected Financial Information

Neither HF Sinclair nor HEP, as a matter of course, publicly discloses long-term financial projections. However, in connection with the proposed Merger, HF Sinclair’s management and the General Partner’s management prepared and provided to the HEP Conflicts Committee on June 12, 2023, certain internal projections (the “Projections”) regarding the future financial performance of HF Sinclair and HEP for the time periods shown

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below. The Projections were used by the HEP Conflicts Committee for the purposes of evaluating the Merger. The Projections also were provided to Intrepid in connection with their financial analysis and opinion as described in the section entitled “ —Opinion of the Financial Advisor to the HEP Conflicts Committee,” and to Barclays in connection with Barclays’ role as financial advisor to HF Sinclair as described in the section entitled “ —Financial Advisor Discussion Materials Provided to HF Sinclair.”

A summary of the Projections is included below to give HF Sinclair Stockholders and HEP Unitholders access to certain unaudited projections that were made available to the HEP Conflicts Committee and its advisors in connection with the Merger.

HF Sinclair and HEP each caution you that uncertainties are inherent in projections of any kind. None of HF Sinclair, HEP or any of their respective affiliates, officers, directors, advisors or other representatives has made or makes any representation or can give any assurance to any HF Sinclair Stockholder or HEP Unitholder regarding the ultimate performance of HF Sinclair or HEP compared to the summarized information set forth below or that any projected results will be achieved.

The Projections were prepared solely for internal use and are subjective in many respects. There can be no assurance that these Projections will be realized or that actual results will not be significantly higher or lower than forecasted. In addition, the Projections were not prepared with a view toward public disclosure or toward complying with GAAP, the published guidelines of the SEC regarding projections or the use of non-GAAP financial measures or the guidelines established by the American Institute of Certified Public Accountants for preparation and presentation of prospective financial information. The Projections included in this joint proxy statement/prospectus have been prepared by, and are the responsibility of, HF Sinclair management and the General Partner’s management. Each of Ernst & Young LLP and KPMG LLP has not audited, reviewed, examined, compiled nor applied agreed-upon procedures with respect to the accompanying Projections and, accordingly, neither Ernst & Young LLP nor KPMG LLP expresses an opinion or any other form of assurance with respect thereto. The Ernst & Young LLP reports incorporated by reference in this joint proxy statement/prospectus relate to HF Sinclair’s and HEP’s respective historical financial information. The KPMG LLP reports incorporated by reference in this joint proxy statement/prospectus relate to Hippo Holding, LLC (now known as Sinclair Holding LLC) and subsidiaries’ and Sinclair Transportation Company LLC and subsidiaries’ respective historical financial information. Such reports do not extend to the Projections and should not be read to do so.

While presented with numerical specificity, the Projections for the periods shown reflect numerous estimates and assumptions made by HF Sinclair management and the General Partner’s management with respect to industry performance and competition, general business, economic, market and financial conditions and matters specific to each of HF Sinclair’s and HEP’s businesses, all of which are difficult to predict and many of which are beyond HF Sinclair’s and HEP’s control. In developing the Projections for the periods shown below, HF Sinclair management and the General Partner’s management made numerous material assumptions with respect to HF Sinclair and HEP for the periods covered by such Projections, including assumptions regarding:

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Important factors that may affect actual results and cause these financial projections not to be achieved include, but are not limited to, risks and uncertainties relating to HF Sinclair’s and HEP’s business (including the ability to achieve strategic goals, objectives and targets over the applicable periods), industry performance, general business and economic conditions, the regulatory environment and other factors described in or referenced under “Cautionary Statement Regarding Forward-Looking Statements” and those risks and uncertainties detailed in HF Sinclair’s and HEP’s public filings with the SEC. In addition, the Projections also reflect assumptions that are subject to change and do not and will not reflect revised prospects for HF Sinclair’s and HEP’s business, changes in general business or economic conditions or any other transaction or event that has occurred or that may occur following the time the Projections were prepared and provided in early June 2023. Accordingly, there can be no assurance that these Projections will be realized or that future financial results will not materially vary from these Projections.

In addition, the inclusion of the following Projections in this joint proxy statement/prospectus should not be regarded as an indication that HF Sinclair, HEP or their respective financial advisors or other representatives considered or consider the Projections to be necessarily indicative of actual future performance or events, and the Projections set forth below should not be relied upon as such. Accordingly, HF Sinclair Stockholders and HEP Unitholders are cautioned not to place undue reliance on the Projections. The summaries of the Projections provided to the HEP Conflicts Committee are not included in this joint proxy statement/prospectus in order to induce any HF Sinclair Stockholder or HEP Unitholder to vote in favor of the HF Sinclair Stock Issuance Proposal or the Merger Proposal, as applicable. By including in this joint proxy statement/prospectus a summary

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of certain of the Projections, none of HF Sinclair, HEP or any of their respective financial advisors or other representatives have made or are making any representation to any person regarding the ultimate performance of HF Sinclair or HEP. The Projections cover multiple years and are highly dependent on volatile commodities pricing; such information by its nature becomes less predictive with each succeeding year.

The following table sets forth a summary of the Projections with respect to HF Sinclair and HEP for the periods shown below:

Reconciliations of forward-looking non-GAAP financial measures to comparable GAAP measures are not available because certain information needed to make a reasonable forward-looking estimate of the most comparable GAAP measures is difficult to estimate or not available and dependent on future events which may be uncertain or outside of HF Sinclair’s and HEP’s control. Accordingly, a reconciliation is not available without unreasonable effort or expense.

NONE OF HF SINCLAIR OR HEP (OR ANY OF THEIR RESPECTIVE AFFILIATES, OFFICERS, DIRECTORS OR MANAGERS) INTENDS TO REVISE ANY FINANCIAL PROJECTIONS, WHICH, FOR THE AVOIDANCE OF DOUBT, SPEAK ONLY TO MANAGEMENT’S PROJECTIONS AS OF THE DATE SUCH PROJECTIONS WERE MADE, INCLUDED IN THIS JOINT PROXY STATEMENT/PROSPECTUS AFTER THE DATE WHEN MADE OR TO REFLECT THE OCCURRENCE OF FUTURE EVENTS, EVEN IF ANY OR ALL OF THE ASSUMPTIONS UNDERLYING SUCH PROJECTIONS ARE NO LONGER APPROPRIATE.

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Primary Benefits and Detriments of the Merger

The primary benefits of the Merger to the HEP Unaffiliated Unitholders, who will not have a continuing interest in HEP following the Merger, include the following:

The primary detriments of the Merger to the HEP Unaffiliated Unitholders, who will not have a continuing interest in HEP following the Merger, include the following:

Benefits and Detriments to HEP, the General Partner and the Parent Entities

The primary benefits of the Merger to HEP, the General Partner and the Parent Entities include the following:

The primary detriments of the Merger to HEP, the General Partner and the Parent Entities include the following:

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Financial Advisor Discussion Materials Provided to HF Sinclair

HF Sinclair retained Barclays to act as its financial advisor in connection with evaluating the Merger. Barclays provided, at HF Sinclair’s request, the Barclays Discussion Materials.

The Barclays Discussion Materials are included as an exhibit to the Schedule 13E-3 relating to the Merger and are incorporated herein by reference in their entirety. The description of the Barclays Discussion Materials set forth below is qualified in its entirety by reference to the full text of such materials. You are urged to read the Barclays Discussion Materials carefully and in their entirety. The Barclays Discussion Materials were provided for the information and benefit of HF Sinclair in connection with its evaluation of the Merger. Barclays was not requested to, and it did not, provide to HF Sinclair or any other person any (i) opinion (whether as to the fairness of any consideration, including, without limitation, the Merger Consideration, or otherwise), (ii) valuation of HEP for the purpose of assessing the fairness of the Merger Consideration to any person, or (iii) recommendation as to how to vote or act on any matters relating to the proposed Merger or otherwise. The Barclays Discussion Materials were provided for the use and benefit of HF Sinclair in its consideration of the Merger and did not address the relative merits of the Merger as compared to any alternative transaction or opportunity that might be available to HF Sinclair or HEP, nor did they address the underlying business decision by HF Sinclair or HEP to engage in the Merger or to agree to the terms of the Merger Agreement or the documents referred to therein. The Barclays Discussion Materials were informational and were based on financial projections and other information and data available to Barclays as of the date such materials were prepared rather than as of the date of the execution of the Merger Agreement. Because Barclays was not requested to, and did not, deliver a fairness opinion in connection with the Merger, it did not follow and was not required to follow all of the procedures in preparing the Barclays Discussion Materials that it would ordinarily follow in connection with delivering an opinion. The Barclays Discussion Materials should not be construed as creating any fiduciary duty on Barclays’ part to HF Sinclair or any other person and such materials are not intended to be, and do not constitute, a recommendation to HF Sinclair or any other person in respect of the Merger, including as to how any HEP Unitholder should act or vote in respect of the Merger Proposal or as to how any HF Sinclair Stockholder should act or vote in respect of the HF Sinclair Stock Issuance Proposal.

In preparing the Barclays Discussion Materials, Barclays assumed and relied upon the accuracy and completeness of the financial and other information (including but not limited to with respect to the business, operations and prospects of HEP and HF Sinclair furnished to Barclays by HF Sinclair, including financial projections of HEP prepared by the management of the General Partner and financial projections of HF Sinclair prepared by the management of HF Sinclair) used by Barclays without any independent verification of such information (and did not assume responsibility or liability for any independent verification of such information). Barclays also relied upon the assurances of the management of HF Sinclair that they are not aware of any facts or circumstances that would make such information inaccurate or misleading. With respect to the financial projections relating to HEP and HF Sinclair furnished to Barclays by HF Sinclair, including financial projections of HEP prepared by the management of the General Partner and financial projections of HF Sinclair prepared by the management of HF Sinclair, upon the advice of HF Sinclair, Barclays assumed that such projections were reasonably prepared on a basis reflecting the best currently available estimates and good faith judgments of the management of the General Partner and the management of HF Sinclair as to the future financial performance of HEP and HF Sinclair, respectively, and that HEP and HF Sinclair will perform substantially in accordance with such projections. Barclays assumed no responsibility for and expressed no view as to any such projections or estimates or the assumptions on which they were based. Barclays assumed no responsibility for updating or revising the Barclays Discussion Materials for events or circumstances that may have occurred after the date thereof.

In connection with preparing the Barclays Discussion Materials, Barclays reviewed (i) a comparison of the historical financial results and present financial condition of HEP and HF Sinclair with those of other companies that Barclays deemed relevant, (ii) a comparison of the financial terms of the Merger with the financial terms of

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certain other transactions that Barclays deemed relevant, (iii) published estimates of independent research analysts with respect to the future financial performance and price targets of HF Sinclair and HEP and (iv) financial and operating information with respect to the business, operations and prospects of HEP and HF Sinclair furnished to Barclays by HF Sinclair, including financial projections of HEP prepared by the management of the General Partner and financial projections of HF Sinclair prepared by the management of HF Sinclair. In addition, Barclays had discussions with the management of HF Sinclair and the management of the General Partner concerning their respective business operations, assets, liabilities, financial condition and prospects and undertook such other studies, analyses and investigations as Barclays deemed appropriate.

For purposes of its analysis and preparing the Barclays Discussion Materials, Barclays assumed that the executed Merger Agreement would conform in all material respects to the last draft reviewed by Barclays prior to the delivery of the Barclays Discussion Materials. Additionally, Barclays assumed the accuracy of the representations and warranties contained in the Merger Agreement and all the agreements related thereto. Barclays further assumed, in all respects material to its analysis, that all governmental, regulatory or other consents, approvals or releases necessary for the consummation of the Merger will be obtained without any material delay, limitation, restriction or condition.

Barclays did not conduct a physical inspection of the properties or facilities of HEP or HF Sinclair, and Barclays did not make, nor assume any responsibility for making, any independent valuation or appraisal of the assets or liabilities (including any contingent, derivative or other off-balance sheet assets and liabilities) of HEP or HF Sinclair, nor was Barclays furnished with any such valuations or appraisals, nor did Barclays evaluate the solvency or fair value of HEP or HF Sinclair under any state or federal laws relating to bankruptcy, insolvency or similar matters. The Barclays Discussion Materials were necessarily based upon information made available to Barclays as of the date of such materials and financial, economic, market and other conditions as they existed and as could be evaluated on the date of such materials. It is understood that subsequent developments may affect the Barclays Discussion Materials and that Barclays does not have any obligation to update, revise or reaffirm such materials.

Barclays was not asked to pass upon and expressed no opinion with respect to any matter. Barclays did not express any view on, and the Barclays Discussion Materials did not address, the fairness of the Merger to, or any consideration (including the Merger Consideration) received in connection therewith by, the holders of any class of securities, creditors or other constituencies of HEP, nor as to the fairness of the amount or nature of any compensation to be paid or payable to any of the officers, directors or employees of HEP, or any class of such persons, whether relative to the Merger Consideration or otherwise. Barclays was not asked to pass upon, did not express any view on, and the Barclays Discussion Materials did not address, any term or aspect of any other agreement or instrument contemplated by the Merger Agreement or entered into or amended in connection with the Merger Agreement.

Barclays did not address the relative merits of the Merger as compared to other business or financial strategies that might have been available to HF Sinclair or HEP, nor did it address the underlying business decision of HF Sinclair or HEP to engage in the Merger. Barclays was not authorized to solicit, and did not solicit, interest from any third party with respect to the acquisition of any or all of the HEP Common Units or any business combination or other extraordinary transaction involving HF Sinclair or HEP. Barclays did not make, and the Barclays Discussion Materials did not constitute, a recommendation to HF Sinclair or to any other persons in respect of the Merger, including as to how any HEP Unitholder should vote or act in respect of the Merger or as to how any HF Sinclair Stockholder should act or vote in respect of the HF Sinclair Stock Issuance Proposal. Barclays did not express any opinion as to the price at which the HEP Common Units would trade at any time. Barclays was not requested to, and did not, provide any tax advice or express any opinion as to any tax or other consequences that might result from the Merger, nor did Barclays address any legal, tax, regulatory or accounting matters, as to which Barclays understood HF Sinclair had obtained such advice as it deemed necessary from other qualified professionals.

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Summary of Barclays Discussion Materials

The following description of the Barclays Discussion Materials is qualified in its entirety by reference to the relevant Barclays Discussion Materials included as an exhibit to the Schedule 13E-3 related to the Merger, which is incorporated herein by reference. Such description is a summary of the materials prepared by Barclays; however, such summary is not an exhaustive description of the analyses or data presented by Barclays, nor does it represent the relative importance or weight given to those analyses by Barclays.

Barclays made a written presentation to HF Sinclair dated August 14, 2023 that, among other things:

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Except as otherwise noted, the quantitative information included in the August 14, 2023 presentation, to the extent that it was based on market data, was based on market data that existed on August 11, 2023, and is not necessarily indicative of current market conditions.

A copy of the Barclays Discussion Materials is attached as an exhibit to the Schedule 13E-3 related to the Merger.

General

Barclays is an internationally recognized investment banking firm and, as part of its investment banking activities, is regularly engaged in financial advisory services in connection with mergers and acquisitions, investments for passive and control purposes, negotiated underwritings, competitive bids, secondary distributions of listed and unlisted securities, private placements and valuations for estate, corporate and other purposes.

HF Sinclair engaged Barclays to act as its financial advisor in connection with the proposed transaction pursuant to an engagement letter dated as of April 4, 2023, by and between Barclays and HF Sinclair. Accordingly, as compensation for Barclays’ services in connection with the Merger, HF Sinclair will pay Barclays a fee of $6,000,000 upon completion of the Merger. In addition, HF Sinclair has agreed to reimburse Barclays for its reasonable out-of-pocket expenses incurred in connection with the Merger and to indemnify Barclays for certain liabilities that may arise out of its engagement.

Barclays has performed various investment banking and financial services for HF Sinclair, HEP, and their respective affiliates in the past, and is likely to perform such services in the future, and has received, and is likely to receive, customary fees for such services. Specifically, in the past two years, Barclays and its affiliates have performed, or currently are performing, certain investment banking and financial services specifically for HF Sinclair and HEP and have received customary fees for rendering such services.

During the past two years, the aggregate fees received by Barclays that were attributed to HF Sinclair and its affiliates, according to Barclays’ systems and processes, were less than $1,000,000 in investment banking fees. During the past two years, the aggregate fees received by Barclays that were attributed to HEP and its affiliates, according to Barclays’ systems and processes, were less than $1,000,000 in investment banking fees. In the future, Barclays and its affiliates may provide additional investment banking and financial services to HF Sinclair and its affiliates and may receive customary fees for rendering such services.

Barclays, its subsidiaries and its affiliates engage in a wide range of businesses from investment and commercial banking, lending, asset management and other financial and non-financial services. In the ordinary course of its business, Barclays and its affiliates may actively trade and effect transactions in the equity, debt and/or other securities (and any derivatives thereof) and financial instruments (including loans and other obligations) of HF Sinclair or HEP and 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 and investments in such securities and financial instruments.

Other Presentations by Barclays

In addition to the Barclays Discussion Materials, Barclays made, at HF Sinclair’s request, other written and oral presentations to HF Sinclair and the HF Sinclair Board on May 3, 2023 and to HF Sinclair and the HF Sinclair Conflicts Committee on May 3, 2023, July 19, 2023, July 21, 2023, August 1, 2023 and August 11, 2023, which are referred to herein as the “preliminary Barclays presentations.” Copies of the preliminary Barclays presentations have been attached as exhibits to the Schedule 13E-3 related to the Merger. The description of the preliminary Barclays presentations set forth below is qualified in its entirety by reference to the full text of such materials. Such description is a summary of the preliminary presentations prepared by Barclays; however, such summary is not an exhaustive description of the analyses and data presented by Barclays, nor does it represent the relative importance or weight given to those analyses by Barclays.

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None of these preliminary Barclays presentations, alone or together, constitutes an opinion of Barclays with respect to the Merger (whether as to the fairness of any consideration, including, without limitation, the Merger Consideration, or otherwise).

Each of the analyses performed in these preliminary Barclays presentations was subject to further updating and subject to the Barclays Discussion Materials presented to HF Sinclair, the HF Sinclair Conflicts Committee and the HF Sinclair Board on August 14, 2023. Each of these presentations were informational and were based on financial projections and other information and data available to Barclays as of the date such materials were prepared.

The preliminary illustrative materials dated May 1, 2023 (presented on May 3, 2023) were substantially identical to the Barclays Discussion Materials, other than containing earlier pricing data and information, as well as additional slides on the simplified organizational structure of the parties, the rationale and considerations of HF Sinclair and HEP for the Merger and an investor overlap analysis between HF Sinclair and HEP.

The preliminary illustrative materials dated July 19, 2023 (presented on July 19, 2023) were substantially identical to the Barclays Discussion Materials, other than containing earlier pricing and offer data, as well as an additional slide on a precedent transaction deemed relevant to Barclays’ presentation.

The preliminary illustrative materials dated July 21, 2023 (presented on July 21, 2023) were substantially identical to the Barclays Discussion Materials, other than containing earlier pricing and offer data and information, as well as an additional slide on a precedent transaction deemed relevant to Barclays’ presentation.

The preliminary illustrative materials dated August 1, 2023 (presented on August 1, 2023) were substantially identical to the Barclays Discussion Materials, other than containing earlier pricing and offer data and information, as well as an additional slide on a precedent transaction deemed relevant to Barclays’ presentation.

The preliminary illustrative materials dated August 11, 2023 (presented on August 11, 2023) were substantially identical to the Barclays Discussion Materials, other than containing earlier pricing and offer data and information.

Opinion of the Financial Advisor to the HEP Conflicts Committee

The HEP Conflicts Committee engaged Intrepid to act as its financial advisor. As part of that engagement, the HEP Conflicts Committee requested that Intrepid evaluate the fairness, from a financial point of view, of the Merger Consideration to be received by the HEP Unaffiliated Unitholders. On August 15, 2023, Intrepid delivered to the HEP Conflicts Committee its oral opinion, confirmed by its delivery to the HEP Conflicts Committee of a written opinion dated as of the same date, that, as of the date thereof, and based upon and subject to the assumptions, procedures, factors, qualifications, limitations and other matters set forth in Intrepid’s written opinion, the Merger Consideration is fair, from a financial point of view, to the HEP Unaffiliated Unitholders.

The full text of Intrepid’s written opinion, dated August 15, 2023, which sets forth, among other things, certain of the assumptions made, procedures followed, matters considered, and the qualifications and limitations with respect to the review undertaken by Intrepid, is attached as Annex B to this joint proxy statement/prospectus and is incorporated by reference into this section.

Intrepid provided its opinion for the information and benefit of the HEP Conflicts Committee (in its capacity as such) in connection with its evaluation of the Merger. The opinion does not address HEP’s underlying business decision to enter into the Merger or the relative merits of the Merger as compared with any other strategic alternative that may be available to HEP. The opinion is not intended to be and does not constitute a recommendation to any HEP Unaffiliated Unitholder as to how such HEP Unaffiliated Unitholder should act or vote with respect to the Merger or any other matter. This summary is qualified in its entirety by reference to the full text of the opinion.

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Intrepid’s opinion was necessarily based upon business, market, economic, regulatory and other conditions as they existed on, and were evaluated as of, August 15, 2023. Intrepid assumes no responsibility for updating, revising or reaffirming its opinion based on developments, circumstances or events occurring, or information made available to it, after August 15, 2023. Intrepid’s opinion did not express any opinion as to equity securities or debt securities of HEP or HF Sinclair and the price, trading range or volume at which any securities will trade at any time.

In connection with rendering its opinion, Intrepid, among other things:

For purposes of its analysis and opinion, Intrepid assumed and relied upon the accuracy and completeness of all of the foregoing information and any other financial, accounting, legal, operational, tax, and other information and data provided to, discussed with or reviewed by it, or that was publicly available to it, and Intrepid has not assumed any responsibility for independent verification of the accuracy or completeness of any such information.

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Intrepid further relied upon the assurances of management of the General Partner and HF Sinclair that they are not aware of any facts or circumstances that would make such information inaccurate, incomplete or misleading. With respect to financial forecasts, projections and business plans of HEP and HF Sinclair provided to it, Intrepid relied, with the consent of the HEP Conflicts Committee, upon the assurances of management of the General Partner and HF Sinclair, respectively, that such data had been reasonably prepared on bases reflecting the best currently available estimates and good faith judgments of such management as to the future financial performance of HEP and HF Sinclair, under the assumptions reflected therein. Intrepid expresses no view as to such financial forecasts or any judgments, estimates or assumptions on which they were based. Intrepid relied upon, with the consent of the HEP Conflicts Committee, the assessment of management of the General Partner and HF Sinclair as to: (i) the potential impact on HEP and HF Sinclair of market and other trends and prospects for, and governmental, regulatory and legislative matters relating to or otherwise affecting, the refining and petroleum product and crude oil storage and transportation industries, and U.S. markets, (ii) the potential impact on the operations, results and prospects of HEP and HF Sinclair of the Merger, and (iii) existing and future contracts and relationships, agreements and arrangements with related and third parties that are necessary or desirable for the operation of HEP and HF Sinclair. Intrepid did not undertake an independent analysis of any potential or actual litigation, regulatory action, possible unasserted claims or other contingent liabilities to which HEP or HF Sinclair is or may be a party or is or may be subject. Intrepid also assumed that there were no material changes in the liabilities, financial condition, results of operations, business or prospects of or relating to HEP and HF Sinclair since the date of the latest information relating to HEP or HF Sinclair, as applicable, made available to it. In arriving at its opinion, Intrepid did not conduct a physical inspection of the properties and facilities of HEP or HF Sinclair and did not make or obtain any evaluations or appraisals of their respective assets or liabilities, nor has Intrepid been furnished with any such evaluations or appraisals.

In rendering its opinion, Intrepid assumed (in all respects material to its analysis and with the consent of the HEP Conflicts Committee) that the representations and warranties of each party contained in the Merger Agreement are true and correct, and that each party will perform all of the covenants, undertakings and agreements required to be performed by it under the Merger Agreement, and the Merger will be consummated on the terms described in the Merger Agreement, without any waiver or modification of any terms or conditions contained therein that were material to its analysis. Intrepid assumed that the final executed and delivered versions of all documents reviewed by it in draft form will conform in all material respects to the most recent drafts reviewed by it. Intrepid assumed that all governmental, regulatory or other consents, approvals or releases, including under the HEP Partnership Agreement, and any financing necessary for the consummation of the Merger, will be obtained without any material delay, limitation, restriction or condition that would have an adverse effect on the parties to the Merger or the consummation of the Merger or materially reduce the benefits of the Merger to HEP. Intrepid assumed that the Merger and the business of each of HEP, the General Partner and the other parties to the Merger will be and has been conducted in a manner that complies with all applicable federal, state and local statutes, rules and regulations. Intrepid assumed that HEP, the General Partner and the HEP Conflicts Committee have relied upon the advice of their counsel, independent accountants and other advisors (other than Intrepid) as to all legal, financial reporting, tax, accounting, securities and regulatory matters with respect to the Merger.

Intrepid was not asked to pass upon, and expresses no opinion with respect to, any matter other than whether the Merger Consideration is fair, from a financial point of view, to the HEP Unaffiliated Unitholders. Intrepid was not asked to, nor does it express any view on, and its opinion does not address, any other terms, conditions, aspects or implications of the Merger or any agreements, arrangements or understandings entered into in connection therewith or otherwise, including the structure, form or timing of the Merger, any potential adjustment to the Exchange Ratio and Cash Consideration under the Merger Agreement, and the covenants and undertakings of HEP and HF Sinclair in the Merger Agreement. For purposes of its opinion and analyses, with the permission of the HEP Conflicts Committee, the Merger Consideration is as defined in Intrepid’s opinion, and Intrepid gives no effect or consideration to the potential adjustments to the Merger Consideration provided for in the Merger Agreement. Intrepid’s opinion does not address any financing transactions associated with the Merger. In addition, Intrepid does not express any view regarding the relative merits of the Merger as compared to any other transaction or business strategy in which HEP might engage or the merits of the underlying decision

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by the GP Board to cause HEP to engage in the Merger and enter into and perform under the Merger Agreement. Intrepid expresses no view or opinion as to the fairness of the Merger to any creditors, bondholders or other constituencies of HEP (other than the HEP Unaffiliated Unitholders, as described in Intrepid’s opinion) or its subsidiaries, or the fairness of the amount or nature of, or any other aspects relating to, the compensation to any officers, directors or employees of any parties to the Merger or class of such persons, relative to the Merger Consideration or otherwise. Further, the HEP Conflicts Committee did not authorize Intrepid to solicit, and Intrepid did not solicit, any indications of interest from any third party with respect to any alternative transaction to the Merger.

Intrepid’s opinion does not address accounting, legal, actuarial, regulatory or tax matters. Intrepid is not a legal, tax, commercial or bankruptcy advisor. Intrepid’s opinion does not constitute a solvency opinion and does not address the solvency or financial condition of HEP or any of the potential parties to the Merger. Intrepid’s opinion does not address whether HEP has sufficient cash available or other sources of funds to enable it to consummate any distributions. Intrepid’s opinion does not constitute a tax opinion. Intrepid’s opinion cannot be used by any taxpayer for the purpose of avoiding tax penalties that may be imposed on such taxpayer. Each person should seek legal, regulatory, accounting and tax advice based on his, her or its particular circumstances from independent advisors regarding the evaluation and impact of any transactions or matters described herein.

Intrepid does not express any opinion as to equity securities or debt securities of HEP or HF Sinclair and the price, trading range or volume at which any securities will trade at any time, including following announcement of the Merger.

In arriving at its opinion, Intrepid did not attribute any particular weight to any particular analysis or factor considered by it, but rather made qualitative judgments as to the significance and relevance of each analysis and factor. Several analytical methodologies were employed by Intrepid in its analyses, and no one single method of analysis should be regarded as critical to the overall conclusion reached by Intrepid. Each analytical technique has inherent strengths and weaknesses, and the nature of the available information may further affect the value of particular techniques. Accordingly, Intrepid believes that its analyses must be considered as a whole and that selecting portions of its analyses and of the factors considered by it, without considering all analyses and all factors in their entirety, could create a misleading or incomplete view of the evaluation process underlying its opinion. The conclusion reached by Intrepid, therefore, is based on the application of Intrepid’s own experience and judgment to all analyses and factors considered by it, taken as a whole. Intrepid’s opinion was approved by the fairness opinion committee of Intrepid.

Summary of Material Financial Analyses

Set forth below is a summary of the material financial analyses performed by Intrepid and reviewed with the HEP Conflicts Committee on August 15, 2023, in connection with rendering Intrepid’s opinion to the HEP Conflicts Committee.

Financial data for HEP and HF Sinclair utilized in the financial analyses described below were based on, among other things, financial projections of HEP, on a standalone basis as prepared by the management of the General Partner (which is referred to in this section as the “HEP Base Case”), and financial projections of HF Sinclair prepared by the management of HF Sinclair (which is referred to in this section as the “HF Sinclair Base Case”). The management of the General Partner consists of certain members of the management of HF Sinclair. Please see “Business and Background of Natural Persons” beginning on page 171. At the direction of the HEP Conflicts Committee, Intrepid also analyzed a sensitivity case (the “Sensitivity Case”) sensitizing the Renewables and Lubricants segments of HF Sinclair, which reflects an alternative forecast that is more conservative than the HF Sinclair Base Case. The HEP Base Case and the HF Sinclair Base Case are further described under “—Unaudited Projected Financial Information” on page 62.

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The following is a summary of the material financial analyses performed by Intrepid with respect to each of HEP and HF Sinclair in preparing Intrepid’s opinion:

HEP

HF Sinclair

In addition, Intrepid performed certain other analyses that were reviewed with the HEP Conflicts Committee. As reference analyses, Intrepid reviewed research analyst price targets included in equity research from certain investment banks and performed a 52-week market trading analysis for HEP Common Units and HF Sinclair Common Stock.

The following summary does not purport to be an exhaustive description of the financial and comparative analyses performed by Intrepid, nor does the order of analyses described represent relative importance or weight given to those analyses by Intrepid. The preparation of a fairness opinion is a complex analytic process involving various determinations as to the most appropriate and relevant methods of financial analysis and the application of those methods to the particular circumstances. A fairness opinion is thus not susceptible to partial analysis or summary descriptions.

The financial and comparative analyses summarized below include information presented in tabular format. In order to fully understand the analyses performed by Intrepid, the tables must be read together with the text of each summary. The tables alone do not constitute a complete description of the financial and comparative analyses performed by Intrepid. Considering the data set forth in the tables below without considering the full narrative description of the analyses, including the methodologies and assumptions underlying the analyses, could create a misleading or incomplete view of the financial and comparative analyses performed by Intrepid. Except as otherwise noted, the following quantitative information is based on market data or conditions as they existed at the time of the delivery of the opinion, on August 15, 2023, and is not necessarily indicative of current market conditions.

Analysis of HEP

Comparable Company Trading Analysis

Intrepid performed a comparable company trading analysis of HEP by reviewing and comparing the market values and trading multiples of the following publicly traded companies that Intrepid deemed to have certain characteristics similar to those of HEP:

Liquids Transportation and Storage companies:

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Small Cap MLP companies:

These companies are referred to in this section as the “HEP selected comparable companies.” Intrepid performed the comparable company trading analysis based on data derived from public company filings and disclosures, publicly available disclosures and broker research estimates. Although none of the HEP selected comparable companies are directly comparable to HEP, the companies included were selected because they are midstream MLP companies with operations, asset profiles, financial profiles, service profiles, geographic exposure and/or entity structure that, in Intrepid’s experience and professional judgment, for purposes of this analysis, may be considered similar to certain aspects of those of HEP. Accordingly, Intrepid believes that purely quantitative analyses are not, in isolation, determinative in the context of the Merger and that qualitative judgments concerning differences between the financial and operating characteristics and prospects of HEP and the HEP selected comparable companies are also relevant.

For each of the HEP selected comparable companies, Intrepid calculated the following trading multiples based on information from public company filings and disclosures, publicly available disclosure statements and broker research estimates, using applicable market data as of August 14, 2023, including:

For purposes of its analysis, in its professional judgment, Intrepid reviewed all trading multiples and ratios for the HEP selected comparable companies. The resulting mean and median trading multiples and ratios of the HEP selected comparable companies are set forth below.

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The table below includes relevant multiple reference ranges selected by Intrepid based on the trading multiples of the HEP selected comparable companies set forth above and Intrepid’s professional judgment.