Maturity Extension Letter (Amendment No. 4) to Letter of Credit Agreement and Subsidiary Guaranty Agreement dated as of July 13, 2017 among NuStar Logistics, L.P., NuStar Energy L.P., the Lenders party thereto and The Bank of Tokyo-Mitsubishi UFJ, Ltd., as Issuing Bank and Administrative Agent

NuStar Logistics L.P.

NuStar Energy L.P.

Attention: Thomas R. Shoaf, Executive Vice President and Chief Financial Officer

Reference is made to (i) that certain Letter of Credit Agreement, dated as of September 3, 2014 (the “Original Agreement”), (ii) that certain Amendment No.1 to Letter of Credit Agreement and Subsidiary Guaranty Agreement dated as of November 3, 2014 (the “Amendment No. 1”), (iii) that certain Maturity Date Extension Letter Amendment dated on or about August 18, 2015 (the “2015 Extension Letter”) and (iv) that certain Maturity Date Extension Letter Amendment dated on or about July 15, 2016 (the “2016 Extension Letter”, together with the Original Agreement, Amendment No. 1, the 2015 Extension Letter, and as further amended, restated, supplemented or otherwise modified from time to time, the “Agreement”) by and among NuStar Logistics, L.P. and NuStar Energy L.P., both Delaware limited partnerships (together the “NuStar Parties”), the lenders from time to time a party thereto (the “Lenders”), and The Bank of Tokyo Mitsubishi UFJ, Ltd., as Issuing Bank and Administrative Agent (the “Agent”). Capitalized terms used but not defined herein shall have the respective meanings given to such terms in the Agreement.

Whereas the Amendment was entered into as of November 3, 2014 and the Agreement was intended to expire as of September 2, 2017, and whereas the Lenders, the NuStar Parties and the Agent mutually wish to extend the expiry of the Agreement until September 2, 2018, now therefore, for good and reasonable consideration, the sufficiency of which is hereby acknowledged, the term “Maturity Date” as set forth in the Agreement is hereby amended to read “September 2, 2018” and Schedule 3.12 to the Agreement is hereby deleted in its entirety and replaced with Schedule 3.12 attached hereto.

No other provision of the Agreement is amended by this letter. The NuStar Parties hereby confirm that the Agreement remains in full force and effect as amended hereby, and that all obligations of such NuStar parties set forth therein are ratified and reconfirmed. The execution, delivery and effectiveness of this letter shall not, except as expressly provided herein, operate as a waiver of any right, power or remedy of any Lender or the Agent under the Agreement or any of the Loan Documents, nor constitute a waiver of any provision of the Agreement or any of the Loan Documents. This Agreement shall be construed in accordance with and governed by the law of the State of New York.

Regards,

CORPORATION, as Lender

THE BANK OF TOKYO-MITSUBISHI UFJ, LTD., as Issuing Bank and a Lender

THE BANK OF TOKYO-MITSUBISHI UFJ, LTD., as Administrative Agent