Marathon Oil (MRO)

If to United States Steel, to:

United States Steel Corporation

600 Grant Street

Pittsburgh, PA 15219

Attn: Chief Tax Officer

412-433-5086 (facsimile)

or any other address or facsimile number as such party may hereafter specify in writing for this purpose by written notice to the other parties to this Agreement. Each such notice, request or other communication under this section shall be deemed to have been duly given (i) on the date of service if served personally on the party to whom notice is given, (ii) on the day of transmission if sent via facsimile transmission to the facsimile number given above; provided that, telephonic confirmation of receipt is obtained promptly after completion of transmission, (iii) on the business day after delivery to an overnight courier service or the express mail service maintained by the United States Postal Service; provided that, receipt of delivery has been

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confirmed, or (iv) on the fifth day after mailing; provided that, receipt of delivery is confirmed, if mailed to the party to whom notice is to be given, by first class mail, registered or certified, postage prepaid, properly addressed and return-receipt requested.

SECTION 12.04. Amendments; No Waivers.

(a) Any provision of this Agreement may be amended, supplemented, or waived if, and only if, such amendment, supplement, or waiver is in writing and signed by the parties.

(b) Notwithstanding any other section of this Agreement, no failure or delay by any party in exercising any right, power or privilege hereunder shall operate as a waiver thereof, nor shall any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege. The rights and remedies provided in this Agreement shall be cumulative and not exclusive of any rights or remedies provided by law.

SECTION 12.05. Damages.

The remedy for any failure or delay in satisfying the obligations contained herein shall be limited to the actual damages suffered as a result of such failure or delay, including interest as provided in Section 10.03 of this Agreement for any late payments.

SECTION 12.06. Expenses.

(a) Except as otherwise provided in this Agreement, each party shall bear its own costs and expenses (including, without limitation, attorneys’ fees and other professional fees and expenses).

(b) Without limiting the generality of Section 12.06(a), each party shall bear the costs and expenses in connection with the preparation for or conduct of any Tax Proceeding that is not an audit (i) with respect to Tax Items that are allocated to such party under this Agreement, and/or (ii) with respect to which such party has an indemnification obligation under Article 7 of this Agreement.

SECTION 12.07. Information for Shareholders.

United States Steel shall provide each USX Shareholder that receives United States Steel stock pursuant to the Distribution with the information necessary for such USX Shareholder to comply with the requirements of Section 355 of the Code and the Treasury Regulations thereunder with respect to any statements that such USX Shareholders must file with their Tax Returns demonstrating the applicability of Section 355 of the Code to the Distribution.

SECTION 12.08. Successors and Assigns.

The provisions of this Agreement shall be binding upon and shall inure to the benefit of the parties to this Agreement and their respective successors (whether by merger, acquisition of assets or otherwise, and, including, without limitation, any successor succeeding to the Tax Attributes of a party under Section 381 of the Code) and assigns, to the same extent as if such successor or assign had been an original party to this Agreement; provided that, except as set forth in this Agreement, no party may assign, delegate or otherwise transfer any of its rights or obligations under this Agreement without the consent of each of the other parties to this Agreement.

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SECTION 12.09. Governing Law.

The application of this Agreement shall be construed in accordance with and governed by the laws of the State of Delaware (regardless of the laws that might otherwise govern under applicable principles of conflicts law) as to all matters, including, without limitation, matters of validity, construction, effect, performance, and remedies.

SECTION 12.10. Changes in Tax Law.

Any reference to a provision of the Code or a law of another jurisdiction shall include a reference to any applicable successor provision or law.

SECTION 12.11. Jurisdiction; Forum.

(a) By the execution and delivery of this Agreement, Marathon and United States Steel submit, and agree to cause their respective affiliates to submit, to the personal jurisdiction of any state or Federal court in the State of Delaware in any suit or proceeding arising out of or relating to this Agreement.

(b) The parties hereto agree that an appropriate and convenient, nonexclusive forum for any disputes between any of the parties hereto or their respective affiliates arising out of this Agreement shall be in any state or Federal court in the State of Delaware.

SECTION 12.12. Counterparts; Effectiveness; No Third Party Beneficiaries.

(a) This Agreement may be signed in any number of counterparts, each of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement shall become effective upon the consummation of the Distribution; provided that, at or before such time, each party to this Agreement shall have received a counterpart of this Agreement signed by the other party. The parties to this Agreement do not intend that any of its provisions will, or do, confer any rights, benefits, remedies, obligations or liabilities under this Agreement upon any person other than (i) the parties to this Agreement, (ii) other members of the Marathon Tax Group, and (iii) other members of the United States Steel Tax Group, together in each case with their respective successors and assigns.

(b) All rights and obligations arising under this Agreement shall survive until they are fully effectuated or performed. Notwithstanding anything in this Agreement to the contrary, this Agreement shall remain in effect and its provisions shall survive for the full period of all applicable statutes of limitation (giving effect to any extension, waiver or mitigation thereof).

SECTION 12.13. Severability.

If any one or more of the provisions of this Agreement should be held invalid, illegal or unenforceable in any respect, the validity, legality and enforceability of the remaining provisions contained in this Agreement shall not in any way be affected or impaired by such holding. The parties shall endeavor in good faith negotiations to replace the invalid, illegal or unenforceable provisions so that the replacement provisions will be valid, legal and enforceable and will have an economic effect which comes as close as possible to that of the invalid, illegal or unenforceable provisions.

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SECTION 12.14. Confidentiality.

Subject to any contrary requirement of law and the right of each party to enforce its rights hereunder in any legal action, each party agrees that it shall keep strictly confidential, and shall cause its employees and agents to keep strictly confidential, any information which it or any of its employees or agents may acquire pursuant to, or in the course of performing its obligations under, any provision of this Agreement.

SECTION 12.15. Interpretation.

The Section headings contained in this Agreement are solely for the purpose of reference, are not part of the agreement of the parties, and shall not in any way affect the meaning or interpretation of this Agreement.

IN WITNESS WHEREOF, the parties to this Agreement have caused this Tax Sharing Agreement to be duly executed by their respective authorized officers as of the date first above written.

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