Marathon Petroleum Corp — Director's Dealing 2012

Oct 24, 2012

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: MPLX LP (MPLX)
CIK: 0001552000
Period of Report: 2012-10-24

Reporting Person: Marathon Petroleum Corp (Director, 10% Owner)
Reporting Person: MPC Investment LLC (Director, 10% Owner)
Reporting Person: MPLX GP LLC (Director)
Reporting Person: MPLX Logistics Holdings LLC (10% Owner)

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Units (Limited Partner Interests)	0	Indirect

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Subordinated Units (Limited Partner Interests)	$0.00		Common Units (0)		Indirect

Footnotes

F1: This Form 3 is filed jointly by Marathon Petroleum Corporation ("MPC"), MPC Investment LLC ("MPC Investment"), MPLX GP LLC (the "General Partner") and MPLX Logistics Holdings LLC ("MPLX Logistics Holdings") in connection with the effectiveness of the Issuer's Registration Statement on Form S-1 (Registration No.333-182500) (the "Registration Statement"). MPC Investment, a direct wholly-owned subsidiary of MPC, owns all of the membership interests in both the General Partner and MPLX Logistics Holdings. Accordingly, the General Partner and MPLX Logistics Holdings are both indirect wholly-owned subsidiaries of MPC.

F2: As of the effectiveness of the Registration Statement, MPLX Logistics Holdings owns a 98% limited partner interest in the Issuer and the General Partner owns a 2% general partner interest in the Issuer. MPC Investment owns all of the membership interests in MPLX Logistics Holdings and the General Partner, and MPC owns all of the membership interest in MPC Investment. Accordingly, MPC and MPC Investment both may be deemed to indirectly beneficially own the securities of the Issuer directly held by the General Partner, but disclaim beneficial ownership except to the extent of their respective pecuniary interests therein. MPC and MPC Investment both may also be deemed to indirectly beneficially own the securities of the Issuer directly held by MPLX Logistics Holdings, but disclaim beneficial ownership except to the extent of their respective pecuniary interests therein.

F3: As described in the Registration Statement, in connection with the closing of the initial public offering of the Issuer, MPC and its subsidiaries will contribute certain assets to the Issuer and MPLX Logistics Holdings will receive: (i) 21,951,515 common units, representing a 29.1% limited partner interest in the Issuer and (ii) 36,951,515 subordinated units, representing a 49% limited partner interest in the Issuer, for a combined 78.1% limited partner interest in the Issuer (or 19,701,515 common units and 36,951,515 subordinated units, representing a combined 75.1% limited partner interest in the Issuer, if the underwriters exercise their option to purchase additional common units in full). The Issuer will also redeem for nominal consideration the current 98% limited partner interest in the Issuer held by MPLX Logistics Holdings.

F4: In connection with the closing of the initial public offering of the Issuer, the General Partner will directly own approximately 1,508,225 general partner units, representing its 2.0% general partner interest in the Issuer.

F5: Each subordinated unit will convert into one common unit at the end of the subordination period described in the Registration Statement.