NTI Northern Tier Energy LP Common Units Representing Limited Partner Interests (delisted)

Contribution Agreement

On September 7, 2016, St. Paul Park Refining Co. LLC (“ SPPR ”), an indirect wholly-owned subsidiary of Western Refining, Inc. (“ Western ”) and wholly-owned subsidiary of Northern Tier Energy LLC, which is a wholly-owned subsidiary of Northern Tier Energy LP (the “ Partnership ”), entered into a Contribution, Conveyance and Assumption Agreement (the “ Contribution Agreement ”) by and among Western, SPPR, Western Refining Logistics, LP (“ WNRL ”) and Western Refining Logistics GP, LLC, the general partner of WNRL (the “ WRGP ”). Pursuant to the terms of the Contribution Agreement, SPPR has agreed to sell to WNRL approximately four million barrels of refined product and crude oil storage tanks, a light products terminal, a heavy products loading rack, certain rail and barge facilities, certain other related logistics assets, and two crude oil pipeline segments and one pipeline segment not currently in service, each of which is approximately 2.5 miles and extends from SPPR’s refinery in St. Paul Park, Minnesota to SPPR’s tank farm in Cottage Grove, Minnesota (collectively, the “ Contributed Assets ”), in exchange for total consideration of $210 million, comprised of $195 million in cash and $15 million of common units representing limited partner interests in WNRL issued to SPPR (the transactions contemplated by the Contribution Agreement, the “ Transaction ”).

The Contribution Agreement has customary representations and warranties regarding the Contributed Assets and the Transaction, as well as customary covenants and indemnity provisions. The parties have agreed to indemnify each other with regards to breaches of their respective representations, warranties and covenants set forth in the Contribution Agreement. The parties have also agreed, subject to certain limitations, to indemnify each other with regards to environmental losses arising from the operation of the Contributed Assets during the parties’ respective periods of ownership of the Contributed Assets. In addition, WNRL has agreed, subject to certain exceptions, to assume the liabilities arising from the ownership and operation of the Contributed Assets and has agreed to indemnify Western with respect to such assumed liabilities.

The consummation of the Transaction is subject to the satisfaction of certain closing conditions, including, among other things, the absence of legal impediments prohibiting the Transaction, the absence of a material adverse effect on the Contributed Assets or the financial condition, liabilities or results of operations of the business relating to the Contributed Assets and the receipt by Western from an independent appraiser of a written certificate stating that the release of the Contributed Assets under the NTI Indenture (as defined in the Contribution Agreement) will not impair the security under the NTI Indenture. There is no assurance that all of the conditions to the consummation of the Transaction will be satisfied. The Partnership currently expects the Transaction to close on or about September 15, 2016.

In connection with the closing of the Transaction, SPPR will enter into a terminalling, transportation and storage services agreement (the “ Terminalling Agreement ”) with Western Refining Terminals, LLC (“ WRT ”), an indirect, wholly-owned subsidiary of WNRL. Pursuant to the Terminalling Agreement, WRT will provide product storage services, product throughput services and product additive and blending services at the terminal facilities located at or near SPPR’s refinery in St. Paul Park, Minnesota. In exchange for such services, SPPR has agreed to certain minimum volume commitments and to pay certain fees. In connection with the execution of the Terminalling Agreement, the Partnership has agreed to guarantee SPPR’s payment obligations under the Terminalling Agreement. The Terminalling Agreement will have an initial term of ten years, which may be extended for up to two renewal terms of five years each upon the mutual agreement of the parties.

The Contribution Agreement is filed as Exhibit 2.1 to this Current Report on Form 8-K, and the foregoing description of the Contribution Agreement is qualified in its entirety by reference to such exhibit.

Relationships

Each of the Partnership, SPPR, WNRL, WRGP and WRT is a direct or indirect subsidiary or affiliate of Western. As a result, certain individuals, including officers and directors of Western and WRGP, serve as officers and/or directors of more than one of such other entities. Western owns through its wholly-owned subsidiaries all of the limited partner interests and general partner interests in the Partnership. Western also owns through its wholly-owned subsidiaries 8,579,623 common units (not including the $15 million of common units to be issued to SPPR in connection with the closing of the Transaction) representing limited partner interests of WNRL and all of the

subordinated units representing limited partner interests in WNRL. In addition, Western owns, through its wholly-owned subsidiary, Western Refining Southwest, Inc., 80,000 units of a class of limited partner interests in WNRL referred to as the “TexNew Mex Units.” WRGP also owns a non-economic general partner interest in WNRL.

Cautionary Statement on Forward-Looking Statements

This Current Report on Form 8-K contains forward-looking statements. The forward-looking statements contained herein include statements about the future: the closing of the Transaction, including (i) the entrance into a terminalling, transportation and storage services agreement and (ii) the satisfaction of closing conditions, including, among other things, the absence of legal impediments prohibiting the Transaction, the receipt by Western of a certificate from an independent appraiser with respect to the release of the Contributed Assets under the NTI Indenture and the absence of a material adverse effect on the Contributed Assets or the financial condition, liabilities or results of operations of the business relating to the Contributed Assets; and the form of the consideration payable to SPPR by WNRL. These statements are subject to the general risks inherent in the Partnership’s businesses and may or may not be realized. Some of the Partnership’s expectations may be based upon assumptions or judgments that prove to be incorrect. In addition, the Partnership’s business and operations involve numerous risks and uncertainties, many of which are beyond the Partnership’s control, which could materially affect the Partnership’s financial condition, results of operations and cash flows. Additional information relating to the uncertainties affecting the Partnership’s business is contained in its filings with the Securities and Exchange Commission. The forward-looking statements are only as of the date made, and the Partnership does not undertake any obligation to (and each expressly disclaims any obligation to) update any forward-looking statements to reflect events or circumstances after the date such statements were made, or to reflect the occurrence of unanticipated events.