MPLX / MPLX LP - Limited Partnership - SEC Filings, Annual Report, Proxy Statement

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 25, 2025 MPLX LP (Exact nam

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 25, 2025 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IR

THIRTY-SECOND SUPPLEMENTAL INDENTURE

EX-4.1 Exhibit 4.1 THIRTY-SECOND SUPPLEMENTAL INDENTURE THIS THIRTY-SECOND SUPPLEMENTAL INDENTURE, dated as of August 11, 2025 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the “Trustee”).

MPLX LP as Issuer, MPLX GP LLC as General Partner, $1,250,000,000 4.800% SENIOR NOTES DUE 2031 $750,000,000 5.000% SENIOR NOTES DUE 2033 $1,500,000,000 5.400% SENIOR NOTES DUE 2035 $1,000,000,000 6.200% SENIOR NOTES DUE 2055 UNDERWRITING AGREEMENT Au

EX-1.1 Exhibit 1.1 EXECUTION VERSION MPLX LP as Issuer, and MPLX GP LLC as General Partner, $1,250,000,000 4.800% SENIOR NOTES DUE 2031 $750,000,000 5.000% SENIOR NOTES DUE 2033 $1,500,000,000 5.400% SENIOR NOTES DUE 2035 $1,000,000,000 6.200% SENIOR NOTES DUE 2055 UNDERWRITING AGREEMENT August 7, 2025 August 7, 2025 To the Representatives named in Schedule I hereto for the Underwriters named in S

THIRTY-FIFTH SUPPLEMENTAL INDENTURE

EX-4.4 Exhibit 4.4 THIRTY-FIFTH SUPPLEMENTAL INDENTURE THIS THIRTY-FIFTH SUPPLEMENTAL INDENTURE, dated as of August 11, 2025 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the “Trustee”). W

THIRTY-THIRD SUPPLEMENTAL INDENTURE

EX-4.2 Exhibit 4.2 THIRTY-THIRD SUPPLEMENTAL INDENTURE THIS THIRTY-THIRD SUPPLEMENTAL INDENTURE, dated as of August 11, 2025 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the “Trustee”). W

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 11, 2025 MPLX LP (Exact na

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 11, 2025 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

THIRTY-FOURTH SUPPLEMENTAL INDENTURE

EX-4.3 Exhibit 4.3 THIRTY-FOURTH SUPPLEMENTAL INDENTURE THIS THIRTY-FOURTH SUPPLEMENTAL INDENTURE, dated as of August 11, 2025 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the “Trustee”).

Security Type

Calculation of Filing Fee Tables S-3 MPLX LP Table 1: Newly Registered and Carry Forward Securities ☐Not Applicable Security Type Security Class Title Fee Calculation or Carry Forward Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Carry Forward Form Type Carry Forward File Number Carry Forward Initial Effective Date Filing Fee Previously Paid in Connection with Unsold Securities to be Carried Forward Newly Registered Securities Fees to be Paid 1 Debt 4.

MPLX LP $1,250,000,000 4.800% Senior Notes due 2031 $750,000,000 5.000% Senior Notes due 2033 $1,500,000,000 5.400% Senior Notes due 2035 $1,000,000,000 6.200% Senior Notes due 2055

424B5 Filed Pursuant to Rule 424(b)(5) Registration No. 333-271922 PROSPECTUS SUPPLEMENT (To Prospectus Dated May 15, 2023) MPLX LP $1,250,000,000 4.800% Senior Notes due 2031 $750,000,000 5.000% Senior Notes due 2033 $1,500,000,000 5.400% Senior Notes due 2035 $1,000,000,000 6.200% Senior Notes due 2055 MPLX LP is offering $1,250,000,000 aggregate principal amount of 4.800% Senior Notes due 2031,

Subject to Completion Preliminary Prospectus Supplement dated August 7, 2025

424B5 Table of Contents The information contained in this preliminary prospectus supplement is not complete and may be changed.

MPLX LP Pricing Term Sheet August 7, 2025 $1,250,000,000 4.800% Senior Notes due 2031 $750,000,000 5.000% Senior Notes due 2033 $1,500,000,000 5.400% Senior Notes due 2035 $1,000,000,000 6.200% Senior Notes due 2055 Issuer: MPLX LP Expected Ratings (

FWP Filed Pursuant to Rule 433 Registration No. 333-271922 August 7, 2025 Supplementing the Preliminary Prospectus Supplement dated August 7, 2025 (To Prospectus dated May 15, 2023) MPLX LP Pricing Term Sheet August 7, 2025 $1,250,000,000 4.800% Senior Notes due 2031 $750,000,000 5.000% Senior Notes due 2033 $1,500,000,000 5.400% Senior Notes due 2035 $1,000,000,000 6.200% Senior Notes due 2055 Is

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 ☐ TRANSITION REPORT PU

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-35714 MPLX LP (Ex

MPLX LP Reports Second-Quarter 2025 Financial Results

Exhibit 99.1 MPLX LP Reports Second-Quarter 2025 Financial Results •Announced Northwind Midstream acquisition for $2.375 billion enhances Permian Natural Gas and NGL value chain and accelerates future growth opportunities •Second-quarter net income attributable to MPLX of $1.0 billion and net cash provided by operating activities of $1.7 billion •Adjusted EBITDA attributable to MPLX of $1.7 billio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 5, 2025 MPLX LP (Exact name

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 5, 2025 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 ☐ TRANSITION REPORT P

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 00

MPLX LP Reports First-Quarter 2025 Financial Results

Exhibit 99.1 MPLX LP Reports First-Quarter 2025 Financial Results •Executing Natural Gas & NGL growth strategy with agreement to acquire 100% ownership in BANGL, LLC and FID of the Traverse natural gas pipeline •First-quarter net income attributable to MPLX of $1.1 billion and net cash provided by operating activities of $1.2 billion •Adjusted EBITDA attributable to MPLX of $1.8 billion, reflectin

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 6, 2025 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Em

Michael J. Hennigan Form of 2025 MPLX Phantom Unit Award Agreement

Exhibit 10.2 MPLX LP PHANTOM UNIT AWARD AGREEMENT MICHAEL J. HENNIGAN As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan, as amended (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to {Participant Name} (the “Participant”), an Empl

Form of 2025 MPLX Phantom Unit Award Agreement

Exhibit 10.1 MPLX LP PHANTOM UNIT AWARD AGREEMENT SENIOR LEADERS (CEO, DESIGNATED POSITIONS & EXECUTIVE RESOURCES) As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan, as amended (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to {P

Third Amendment to the Amended and Restated Transportation Services Agreement, dated January 1, 2025, between Hardin Street Marine LLC and Marathon Petroleum Company LP

Exhibit 10.3 THIRD AMENDMENT TO THE AMENDED AND RESTATED TRANSPORTATION SERVICES AGREEMENT THIS THIRD AMENDMENT (“Amendment”) by and between Marathon Petroleum Company LP, a Delaware limited partnership (“MPC”) and Hardin Street Marine LLC, a Delaware limited liability company (“HSM”) is entered into effective as of January 1, 2025 (the “Amendment Date”). MPC and HSM may be referred to individuall

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 10, 2025 (March 3, 2025) MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission F

Underwriting Agreement, dated as of March 3, 2025, by and among the Issuer, MPLX GP LLC, the general partner of the Issuer, and each of BofA Securities, Inc., Barclays Capital Inc. and J.P. Morgan Securities LLC, acting as representatives of the several underwriters named therein

Exhibit 1.1 EXECUTION VERSION MPLX LP as Issuer, and MPLX GP LLC as General Partner, $1,000,000,000 5.400% SENIOR NOTES DUE 2035 $1,000,000,000 5.950% SENIOR NOTES DUE 2055 UNDERWRITING AGREEMENT March 3, 2025 March 3, 2025 To the Representatives named in Schedule I hereto for the Underwriters named in Schedule II hereto Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the “Partnersh

Thirtieth Supplemental Indenture, dated as of March 10, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)

Exhibit 4.1 Execution Version THIRTIETH SUPPLEMENTAL INDENTURE THIS THIRTIETH SUPPLEMENTAL INDENTURE, dated as of March 10, 2025 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the “Trustee”

Thirty-First Supplemental Indenture, dated as of March 10, 2025, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)

EX-4.2 Exhibit 4.2 Execution Version THIRTY-FIRST SUPPLEMENTAL INDENTURE THIS THIRTY-FIRST SUPPLEMENTAL INDENTURE, dated as of March 10, 2025 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (

Calculation of Filing Fee Table Form S-3 (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities

Exhibit 107 Calculation of Filing Fee Table Form S-3 (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Carry Forward Form Type Carry Forward File Number Carry Forward Initial Effective Date Filing Fee Previously Paid in Connection with Unsold Securities to be Carried Forward Fees to be Paid 1  Debt 5.

MPLX LP $1,000,000,000 5.400% Senior Notes due 2035 $1,000,000,000 5.950% Senior Notes due 2055

Filed Pursuant to Rule 424(b)(5) Registration No. 333-271922 PROSPECTUS SUPPLEMENT (To Prospectus Dated May 15, 2023) MPLX LP $1,000,000,000 5.400% Senior Notes due 2035 $1,000,000,000 5.950% Senior Notes due 2055 MPLX LP, or “MPLX,” “we” or “us,” is offering $1,000,000,000 aggregate principal amount of 5.400% Senior Notes due 2035, which we refer to as the “2035 notes,” and $1,000,000,000 aggrega

Subject to Completion Preliminary Prospectus Supplement dated March 3, 2025

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-271922 The information contained in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell the securities and are not soliciting an offer to buy the securities offered hereby in any jurisdiction where the offer o

MPLX LP Pricing Term Sheet March 3, 2025 $1,000,000,000 5.400% Senior Notes due 2035 $1,000,000,000 5.950% Senior Notes due 2055 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2/BBB/BBB Net proceeds (after underwriting discounts but be

Filed Pursuant to Rule 433 Registration No. 333-271922 March 3, 2025 Supplementing the Preliminary Prospectus Supplement dated March 3, 2025 (To Prospectus dated May 15, 2023) MPLX LP Pricing Term Sheet March 3, 2025 $1,000,000,000 5.400% Senior Notes due 2035 $1,000,000,000 5.950% Senior Notes due 2055 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2/BBB/BBB Net proceeds (after und

List of Subsidiaries

Exhibit 21.1 MPLX LP LIST OF SUBSIDIARIES as of December 31, 2024 Name of Subsidiary Jurisdiction of Organization/Incorporation Andeavor Field Services LLC Delaware Andeavor Gathering I LLC Delaware Andeavor Logistics CD LLC Delaware Andeavor Logistics LLC Delaware Andeavor Midstream Partners GP LLC Delaware Andeavor Midstream Partners LP Delaware Andeavor Midstream Partners Operating LLC Delaware

MPLX LP 2018 Incentive Compensation Plan MPC Non-Employee Director Phantom Unit Award Policy, as amended and restated effective November 15, 2024

Exhibit 10.48 MPLX LP 2018 INCENTIVE COMPENSATION PLAN MPC NON-EMPLOYEE DIRECTOR PHANTOM UNIT AWARD POLICY (Amended and Restated effective as of November 15, 2024) 1. Phantom Unit Awards. Pursuant to this MPC Non-Employee Director Phantom Unit Award Policy (the “Award Policy”) and the MPLX LP 2018 Incentive Compensation Plan (the “Plan”), the Board of Directors of MPLX GP LLC (the “Board”), a Dela

MPLX GP LLC Non-Management Director Compensation Policy, as amended and restated effective November 15, 2024

Exhibit 10.49 MPLX GP LLC NON-MANAGEMENT DIRECTOR COMPENSATION POLICY (as Amended and Restated Effective November 15, 2024) Directors of MPLX GP LLC (the “Company”) who are not employed by the Company or one of its subsidiaries or affiliates (“Non-Management Directors”) shall receive compensation for their services on the Board of Directors of the Company (the “Board”) and related committees as se

Description of Securities

Exhibit 4.3 DESCRIPTION OF THE REGISTRANT’S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 DESCRIPTION OF COMMON UNITS In the text that follows, we have summarized the material provisions of our Sixth Amended and Restated Agreement of Limited Partnership, dated February 1, 2021, as may be amended or amended and restated from time to time (the “Partnership Agree

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-357

Power of Attorney of Directors and Officers of MPLX GP LLC

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned officers and directors of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the “Registrant”), does hereby constitute and appoint Maryann T. Mannen, C. Kristopher Hagedorn and Kelly D. Wright, and each of them, as his or her true and lawful attorne

MPLX LP Senior Leader Change in Control Severance Benefits Plan, as amended and restated effective December 1, 2024

Exhibit 10.50 MPLX LP Senior Leader Change in Control Severance Benefits Plan (As Amended and Restated Effective December 1, 2024) 1.History and Purpose of the Plan; No Duplication of Benefits. The board of directors of MPLX GP LLC, a Delaware limited liability company (the “General Partner”), on behalf of MPLX LP, a publicly-traded Delaware limited partnership (the “Partnership”), and the board o

Trading of Securities Policy

POLICY #5004x Exhibit 19.1 TRADING OF SECURITIES GENERAL PURPOSE To promote prudent individual trading practices and minimize the risk of inadvertent securities law violations by Directors, Officers and other representatives of MPLX GP LLC, the general partner (the “General Partner”) of MPLX LP (the “Partnership”), that could damage the Partnership’s reputation or subject the Partnership or the Ge

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 4, 2025 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

MPLX LP Progresses Gulf Coast NGL Strategy and Reports Full-Year 2024 Results

MPLX LP Progresses Gulf Coast NGL Strategy and Reports Full-Year 2024 Results •Progresses Gulf Coast NGL strategy with announcement of fractionation complex and export terminal •Full-year 2024 net income attributable to MPLX of $4.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) January 22, 2025 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

Ninth Amendment to the Third Amended and Restated Terminal Services Agreement, dated September 1, 2024, between MPLX Terminals LLC and Marathon Petroleum Company LP

Exhibit 10.3 Ninth Amendment to the Third Amended and Restated Terminal Services Agreement This Ninth Amendment to the Third Amended and Restated Terminal Services Agreement ("Amendment") is dated September 1, 2024, by and between Marathon Petroleum Company LP, a Delaware limited partnership with an address of 539 South Main Street, Findlay, Ohio 45840 ("MPC"), and MPLX Terminals LLC, a Delaware l

Ninth Amendment to the Terminal Services Agreement, dated as of August 1, 2024, by and between the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto

Exhibit 10.2 NINTH AMENDMENT TO TERMINAL SERVICES AGREEMENT This Ninth Amendment to Terminal Services Agreement (“Amendment”) is made and entered into as of August 1, 2024 (“Amendment Date”) with respect to each respective Terminal set forth on Schedule I, unless otherwise indicated, the party identified as “Customer” with respect to such respective Terminal as set forth on Schedule I (such party,

MPLX LP 2018 Incentive Compensation Plan MPC Non-Employee Director Phantom Unit Award Policy, as amended and restated October 1, 2024

Exhibit 10.4 MPLX LP 2018 INCENTIVE COMPENSATION PLAN MPC NON-EMPLOYEE DIRECTOR PHANTOM UNIT AWARD POLICY (Amended and Restated effective as of October 1, 2024) Pursuant to this MPC Non-Employee Director Phantom Unit Award Policy (the “Award Policy”) and the MPLX LP 2018 Incentive Compensation Plan (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 ☐ TRANSITION REPO

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file numbe

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 5, 2024 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

MPLX LP Reports Third-Quarter 2024 Financial Results

Exhibit 99.1 MPLX LP Reports Third-Quarter 2024 Financial Results •Third-quarter net income attributable to MPLX of $1.0 billion and net cash provided by operating activities of $1.4 billion •$1.7 billion of adjusted EBITDA attributable to MPLX and $1.4 billion of distributable cash flow •$949 million of capital returned to unitholders •Increased quarterly distribution by 12.5% to $3.83 per unit a

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 11, 2024 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission

by and between MPLX LP and MPC Investment LLC

Exhibit 10.2 SECOND AMENDMENT TO AMENDED AND RESTATED LOAN AGREEMENT THIS SECOND AMENDMENT TO THE AMENDED AND RESTATED LOAN AGREEMENT (“Second Amendment”) is effective as of July 31, 2024, by and between MPLX LP, a Delaware limited partnership (the “Borrower”), and MPC Investment LLC, a Delaware limited liability company (the “Lender”). The Borrower and the Lender may be singularly referred to as

Eighth Amendment to the Terminal Services Agreement, dated as of April 16, 2024, by and between the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto

Exhibit 10.1 EIGHTH AMENDMENT TO TERMINAL SERVICES AGREEMENT This Eighth Amendment to Terminal Services Agreement (“Amendment”) is made and entered into as of April 16, 2024 (“Amendment Date”) with respect to each respective Terminal set forth on Schedule I, unless otherwise indicated, the party identified as “Customer” with respect to such respective Terminal as set forth on Schedule I (such part

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 ☐ TRANSITION REPORT PU

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001

MPLX LP Reports Second-Quarter 2024 Financial Results

Exhibit 99.1 MPLX LP Reports Second-Quarter 2024 Financial Results •Second-quarter net income attributable to MPLX of $1.2 billion and net cash provided by operating activities of $1.6 billion •Adjusted EBITDA attributable to MPLX of $1.7 billion and distributable cash flow of $1.4 billion •Returned $949 million of capital to unitholders •Progressing Permian growth strategy; Preakness II processin

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 6, 2024 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

Underwriting Agreement, dated as of May 15, 2024, by and among the Issuer, MPLX GP LLC, the general partner of the Issuer, and each of Mizuho Securities USA LLC, RBC Capital Markets, LLC and TD Securities (USA) LLC, acting as representatives of the several underwriters named therein

Exhibit 1.1 EXECUTION VERSION MPLX LP as Issuer, and MPLX GP LLC as General Partner, $1,650,000,000 5.500% SENIOR NOTES DUE 2034 UNDERWRITING AGREEMENT May 15, 2024 May 15, 2024 To the Representatives named in Schedule I hereto for the Underwriters named in Schedule II hereto Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the “Partnership”), proposes to issue and sell to the severa

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 20, 2024 MPLX LP (Exact name o

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 20, 2024 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS E

Twenty-Ninth Supplemental Indenture, dated as of May 20, 2024, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)

Exhibit 4.1 EXECUTION VERSION TWENTY-NINTH SUPPLEMENTAL INDENTURE THIS TWENTY-NINTH SUPPLEMENTAL INDENTURE, dated as of May 20, 2024 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the “Trus

Calculation of Filing Fee Table (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maxim

Exhibit 107 Calculation of Filing Fee Table 424(b)(5) (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee(1) Debt 5.

MPLX LP $1,650,000,000 5.500% Senior Notes due 2034

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-271922 PROSPECTUS SUPPLEMENT (To Prospectus Dated May 15, 2023) MPLX LP $1,650,000,000 5.500% Senior Notes due 2034 MPLX LP, or “MPLX,” “we” or “us,” is offering $1,650,000,000 aggregate principal amount of 5.500% Senior Notes due 2034, which we refer to as the “notes.” We will pay interest on the notes semi-annually in arrear

MPLX LP Pricing Term Sheet May 15, 2024 $1,650,000,000 5.500% Senior Notes due 2034 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2/BBB/BBB Net proceeds (after underwriting discounts but before expenses) to the Issuer: $1,619,112,000

Filed Pursuant to Rule 433 Registration No. 333-271922 May 15, 2024 Supplementing the Preliminary Prospectus Supplement dated May 15, 2024 (To Prospectus dated May 15, 2023) MPLX LP Pricing Term Sheet May 15, 2024 $1,650,000,000 5.500% Senior Notes due 2034 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2/BBB/BBB Net proceeds (after underwriting discounts but before expenses) to the

Subject to Completion Preliminary Prospectus Supplement dated May 15, 2024

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-271922 The information contained in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell the securities and are not soliciting an offer to buy the securities offered hereby in any jurisdiction where the offer o

MPLX LP Announces Leadership Transition Effective August 1, 2024

MPLX LP Announces Leadership Transition Effective August 1, 2024 •Maryann Mannen elected President and CEO •Mike Hennigan to transition to Executive Chairman of the Board of Directors FINDLAY, Ohio, May 13, 2024 – MPLX LP (NYSE: MPLX) today announced its leadership transition plan, effective August 1, 2024.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 11, 2024 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS E

MPLX / MPLX LP - Limited Partnership / Marathon Petroleum Corp - SCHEDULE 13D/A AMENDMENT NO. 17 Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Amendment No. 17) Under the Securities Exchange Act of 1934 MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securities) 55336V100 (CUSIP Number) Molly R. Benson Chief Legal Officer and Corporate Secretary Marathon Petroleum Corporation 539 South Main Street Findla

Form of 2024 MPLX Phantom Unit Award Agreement

Exhibit 10.1 MPLX LP PHANTOM UNIT AWARD AGREEMENT SENIOR LEADERS (CEO, DESIGNATED POSITIONS & EXECUTIVE RESOURCES) As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan, as amended (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to {P

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 30, 2024 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 ☐ TRANSITION REPORT P

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 00

Seventh Amendment to the Terminal Services Agreement, dated as of January 31, 2024, by and between the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto

Exhibit 10.2 SEVENTH AMENDMENT TO TERMINAL SERVICES AGREEMENT This Seventh Amendment to Terminal Services Agreement (“Amendment”) is made and entered into as of January 31, 2024 (“Amendment Date”) with respect to each respective Terminal set forth on Schedule I, unless otherwise indicated, the party identified as “Customer” with respect to such respective Terminal as set forth on Schedule I (such

MPLX LP Reports First-Quarter 2024 Financial Results

Exhibit 99.1 MPLX LP Reports First-Quarter 2024 Financial Results •First-quarter net income attributable to MPLX of $1.0 billion and net cash provided by operating activities of $1.3 billion •Adjusted EBITDA attributable to MPLX of $1.6 billion and distributable cash flow of $1.4 billion •Returned $951 million of capital to unitholders •Advanced growth strategy with processing plants in the Marcel

Description of Securities

Exhibit 4.3 DESCRIPTION OF THE REGISTRANT’S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 DESCRIPTION OF COMMON UNITS In the text that follows, we have summarized the material provisions of our Sixth Amended and Restated Agreement of Limited Partnership, dated February 1, 2021, as may be amended or amended and restated from time to time (the “Partnership Agree

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-357

MPLX LP Officer Compensation Clawback Policy

Exhibit 97.1 MPLX LP OFFICER COMPENSATION CLAWBACK POLICY 1. Purpose The purpose of this Officer Compensation Clawback Policy (“Policy”) is to set forth the policy of MPLX LP (the “Company”) on recouping compensation from certain of the Company’s officers and other designated individuals upon the occurrence of specified events. This Policy consolidates (a) in Section 4, certain specific recoupment

List of Subsidiaries

Exhibit 21.1 MPLX LP LIST OF SUBSIDIARIES as of December 31, 2023 Name of Subsidiary Jurisdiction of Organization/Incorporation Andeavor Field Services LLC Delaware Andeavor Gathering I LLC Delaware Andeavor Logistics CD LLC Delaware Andeavor Logistics LLC Delaware Andeavor Midstream Partners GP LLC Delaware Andeavor Midstream Partners LP Delaware Andeavor Midstream Partners Operating LLC Delaware

Power of Attorney of Directors and Officers of MPLX GP LLC

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned officers and directors of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the “Registrant”), does hereby constitute and appoint Michael J. Hennigan, C. Kristopher Hagedorn and Kelly D. Wright, and each of them, as his or her true and lawful attor

MPLX / MPLX LP - Limited Partnership / Blackstone Group Management L.L.C. - SC 13G/A Passive Investment

SC 13G/A 1 d719064dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 4)* MPLX LP (Name of Issuer) Common Units Representing Limited Partnership Interests (Title of Class of Securities) 55336V100 (CUSIP Number) December 31, 2023 (Date of Event which Requires Filing of this Statement) Chec

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) January 30, 2024 MPLX LP (Exact na

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) January 30, 2024 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

MPLX LP Reports Fourth-Quarter and Full-Year 2023 Financial Results

Exhibit 99.1 MPLX LP Reports Fourth-Quarter and Full-Year 2023 Financial Results •Fourth-quarter net income attributable to MPLX of $1.1 billion and adjusted EBITDA of $1.6 billion •Full-year 2023 net income attributable to MPLX of $3.9 billion and adjusted EBITDA of $6.3 billion •Full-year 2023 net cash provided by operating activities of $5.4 billion and distributable cash flow of $5.3 billion •

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 21, 2023 MPLX LP (Exact n

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) December 21, 2023 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (

MPLX LP announces C. Kristopher Hagedorn as Chief Financial Officer

MPLX LP announces C. Kristopher Hagedorn as Chief Financial Officer FINDLAY, Ohio, December 21, 2023 – Michael J. Hennigan, chairman, president and chief executive officer of the general partner of MPLX LP (NYSE: MPLX), today announced that C. Kristopher Hagedorn has been appointed executive vice president and chief financial officer of the general partner of MPLX, effective January 1, 2024. As MP

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 31, 2023 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 ☐ TRANSITION REPO

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file numbe

MPLX LP Reports Third-Quarter 2023 Financial Results

Exhibit 99.1 MPLX LP Reports Third-Quarter 2023 Financial Results •Reported third-quarter net income attributable to MPLX of $918 million and generated net cash provided by operating activities of $1,244 million •Adjusted EBITDA attributable to MPLX of $1,596 million and distributable cash flow of $1,373 million •Returned $799 million in capital to unitholders through distributions •Announced quar

MPLX GP LLC Amended and Restated Non-Management Director Compensation Policy and Director Equity Award Terms

Exhibit 10.1 MPLX GP LLC AMENDED AND RESTATED NON-MANAGEMENT DIRECTOR COMPENSATION POLICY AND DIRECTOR EQUITY AWARD TERMS Effective October 1, 2023 Directors of MPLX GP LLC (the “Company”) who are not employed by the Company or one of its subsidiaries or affiliates (“Non-Management Directors”) shall receive compensation for their services on the Board of Directors of the Company (the “Board”) and

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 29, 2023 MPLX LP (Exact na

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 29, 2023 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 1, 2023 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

Sixth Amendment to the Terminal Services Agreement, dated as of June 30, 2023, by and between the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto

Exhibit 10.2 SIXTH AMENDMENT TO TERMINAL SERVICES AGREEMENT This Sixth Amendment to Terminal Services Agreement (“Amendment”) is made and entered into as of June 30, 2023 (“Amendment Date”) with respect to each respective Terminal set forth on Schedule I, unless otherwise indicated, the party identified as “Customer” with respect to such respective Terminal as set forth on Schedule I (such party,

Intercompany Assignment Agreement of the Terminal Services Agreement, dated as of May 1, 2023, by and between the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto

Exhibit 10.3 INTERCOMPANY ASSIGNMENT AGREEMENT THIS INTERCOMPANY ASSIGNMENT AGREEMENT (“Agreement”) is made and entered into by and between: MARATHON PETROLEUM COMPANY LP (“MPCLP”), and MARATHON PETROLEUM SUPPLY AND TRADING LLC (“MPST”), (together, the “Assignee Entities”); ST. PAUL PARK REFINING CO. LLC, TESORO ALASKA COMPANY LLC, TESORO REFINING & MARKETING COMPANY LLC, and WESTERN REFINING COMP

Fifth Amendment to the Terminal Services Agreement, dated as of June 1, 2023, by and between the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto

Exhibit 10.1 FIFTH AMENDMENT TO TERMINAL SERVICES AGREEMENT This Fifth Amendment to Terminal Services Agreement (“Amendment”) is made and entered into as of June 1, 2023 (“Amendment Date”) with respect to each respective Terminal set forth on Schedule I, unless otherwise indicated, the party identified as “Customer” with respect to such respective Terminal as set forth on Schedule I (such party, a

MPLX LP Reports Second-Quarter 2023 Financial Results

Exhibit 99.1 MPLX LP Reports Second-Quarter 2023 Financial Results •Reported second-quarter net income attributable to MPLX of $933 million and generated net cash provided by operating activities of $1,437 million •Adjusted EBITDA attributable to MPLX of $1,531 million •Distributable cash flow of $1,315 million •Advancing Permian strategy with announcement of seventh gas processing plant and expan

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 ☐ TRANSITION REPORT PU

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001

Eighth Amendment to the Third Amended and Restated Terminal Services Agreement, dated March 1, 2017, between MPLX Terminals LLC and Marathon Petroleum Company LP

Exhibit 10.4 Eighth Amendment to the Third Amended and Restated Terminal Services Agreement This Eighth Amendment to the Third Amended and Restated Terminal Services Agreement ("Amendment") is dated May 9, 2023, by and between Marathon Petroleum Company LP, a Delaware limited partnership with an address of 539 South Main Street, Findlay, Ohio 45840 ("MPC"), and MPLX Terminals LLC, a Delaware limit

POWER OF ATTORNEY

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned directors and officers of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the “Registrant”), does hereby constitute and appoint Michael J. Hennigan, John J. Quaid and Kelly D. Wright, or any of them, each acting alone, as the true and lawful atto

As filed with the Securities and Exchange Commission on May 15, 2023

Table of Contents As filed with the Securities and Exchange Commission on May 15, 2023 Registration No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE

Exhibit 25.2 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) The Bank of New York Mellon Trust Company, N.A. (Exact name of trustee as specified in its charter) N/A (

Calculation of Filing Fee Tables Form S-3 (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title(1) Fee Calculation Rule Amount Registered P

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title(1) Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Proposed Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Carry Forward Form T

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE

Exhibit 25.1 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) The Bank of New York Mellon Trust Company, N.A. (Exact name of trustee as specified in its charter) N/A (

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 1, 2023 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Em

First Amendment dated as of January 1, 2023 to Amended and Restated Loan Agreement dated as of July 31, 2019 by and between MPLX and MPC Investment LLC

Exhibit 10.1 FIRST AMENDMENT TO AMENDED AND RESTATED LOAN AGREEMENT THIS FIRST AMENDMENT TO THE AMENDED AND RESTATED LOAN AGREEMENT (“Amendment”) is effective as of January 1, 2023, by and between MPLX LP, a Delaware limited partnership (the “Borrower”), and MPC Investment LLC, a Delaware limited liability company (the “Lender”). The Borrower and the Lender may be singularly referred to as a “Part

MPLX LP Reports First-Quarter 2023 Financial Results

Exhibit 99.1 MPLX LP Reports First-Quarter 2023 Financial Results •First-quarter net income attributable to MPLX of $943 million and net cash provided by operating activities of $1,227 million, up 14% and 9%, respectively, year over year •Adjusted EBITDA attributable to MPLX of $1,519 million, up 9% year over year •Distributable cash flow of $1,268 million, up 5% year over year •Advancing growth p

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 ☐ TRANSITION REPORT P

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 00

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 2, 2023 MPLX LP (Exact name of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 2, 2023 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Em

Form of 2023 MPLX Phantom Unit Award Agreement

Exhibit 10.45 MPLX LP PHANTOM UNIT AWARD AGREEMENT SENIOR LEADERS (CEO, DESIGNATED POSITIONS & EXECUTIVE RESOURCES) As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan, as amended (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to {

First Amendment to Transportation Services Agreement (Garyville Products System), between Marathon Petroleum Company LP and Marathon Pipe Line LLC

Exhibit 10.44 FIRST AMENDMENT TO TRANSPORTATION SERVICES AGREEMENT THIS FIRST AMENDMENT TO TRANSPORTATION SERVICES AGREEMENT ("First Amendment") is by and between MARATHON PIPE LINE LLC ("MPL''), a Delaware limited liability company, with offices at 539 South Main Street, Findlay, Ohio 45840 and MARATHON PETROLEUM COMPANY LP ("MPC"), a Delaware limited partnership, with offices at 539 South Main S

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-357

Power of Attorney of Directors and Officers of MPLX GP LLC

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned officers and directors of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the “Registrant”), does hereby constitute and appoint Michael J. Hennigan, John J. Quaid and Kelly D. Wright, and each of them, as his or her true and lawful attorney or at

List of Subsidiaries

Exhibit 21.1 MPLX LP LIST OF SUBSIDIARIES as of December 31, 2022 Name of Subsidiary Jurisdiction of Organization/Incorporation * ADCC Pipeline, LLC Delaware Andeavor Field Services LLC Delaware Andeavor Gathering I LLC Delaware Andeavor Logistics CD LLC Delaware Andeavor Logistics GP LLC Delaware Andeavor Logistics LP Delaware * Andeavor Logistics Rio Pipeline LLC Delaware Andeavor Midstream Part

Underwriting Agreement, dated as of February 2, 2023, by and among the Issuer, MPLX GP LLC, the general partner of the Issuer, and each of J.P. Morgan Securities LLC, BofA Securities, Inc. and MUFG Securities Americas Inc., acting as representatives of the several underwriters named therein

EX-1.1 Exhibit 1.1 EXECUTION VERSION MPLX LP as Issuer, and MPLX GP LLC as General Partner, $1,100,000,000 5.00% SENIOR NOTES DUE 2033 $500,000,000 5.65% SENIOR NOTES DUE 2053 UNDERWRITING AGREEMENT February 2, 2023 February 2, 2023 To the Representatives named in Schedule I hereto for the Underwriters named in Schedule II hereto Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the “

Twenty-Eighth Supplemental Indenture, dated as of February 9, 2023, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)

EX-4.2 Exhibit 4.2 EXECUTION VERSION TWENTY-EIGHTH SUPPLEMENTAL INDENTURE THIS TWENTY-EIGHTH SUPPLEMENTAL INDENTURE, dated as of February 9, 2023 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trust

Twenty-Seventh Supplemental Indenture, dated as of February 9, 2023, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)

EX-4.1 Exhibit 4.1 EXECUTION VERSION TWENTY-SEVENTH SUPPLEMENTAL INDENTURE THIS TWENTY-SEVENTH SUPPLEMENTAL INDENTURE, dated as of February 9, 2023 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as tru

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 9, 2023 MPLX LP (Exact na

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 9, 2023 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

MPLX / MPLX LP / Blackstone Group Management L.L.C. - SC 13G/A Passive Investment

SC 13G/A 1 d398671dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 3)* MPLX LP (Name of Issuer) Common Units Representing Limited Partnership Interests (Title of Class of Securities) 55336V100 (CUSIP Number) December 31, 2022 (Date of Event which Requires Filing of this Statement) Chec

MPLX LP $1,100,000,000 5.00% Senior Notes due 2033 $500,000,000 5.65% Senior Notes due 2053

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-248443 PROSPECTUS SUPPLEMENT (To Prospectus Dated August 27, 2020) MPLX LP $1,100,000,000 5.00% Senior Notes due 2033 $500,000,000 5.65% Senior Notes due 2053 MPLX LP, or “MPLX,” “we” or “us,” is offering $1,100,000,000 aggregate principal amount of 5.00% Senior Notes due 2033, which we refer to as the “2033 notes,” and $500,0

Calculation of Filing Fee Table (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maxim

EX-FILING FEES 2 d431922dexfilingfees.htm EX-FILING FEES Exhibit 107 Calculation of Filing Fee Table 424(b)(5) (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Am

MPLX LP Final Pricing Term Sheet February 2, 2023 $1,100,000,000 5.00% Senior Notes due 2033 $500,000,000 5.65% Senior Notes due 2053 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2/BBB/BBB Net proceeds (before expenses) to the Issuer

Filed Pursuant to Rule 433 Registration No. 333-248443 February 2, 2023 Supplementing the Preliminary Prospectus Supplement dated February 2, 2023 (To Prospectus dated August 27, 2020) MPLX LP Final Pricing Term Sheet February 2, 2023 $1,100,000,000 5.00% Senior Notes due 2033 $500,000,000 5.65% Senior Notes due 2053 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2/BBB/BBB Net proce

Subject to Completion Preliminary Prospectus Supplement dated February 2, 2023

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-248443 The information contained in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell the securities and are not soliciting an offer to buy the senior notes offered hereby in any jurisdiction where the

MPLX LP Reports Fourth-Quarter and Full-Year 2022 Financial Results

Exhibit 99.1 MPLX LP Reports Fourth-Quarter and Full-Year 2022 Financial Results •Fourth-quarter net income attributable to MPLX of $816 million and full-year net income of $3.9 billion •Fourth-quarter adjusted EBITDA attributable to MPLX of $1.5 billion and full-year 2022 adjusted EBITDA of $5.8 billion •Full-year 2022 net cash provided by operating activities of $5.0 billion and over $3.5 billio

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) January 31, 2023 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 16, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 1, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

MPLX LP Reports Third-Quarter 2022 Financial Results

Exhibit 99.1 MPLX LP Reports Third-Quarter 2022 Financial Results ?Reported third-quarter net income attributable to MPLX of $1,428 million; includes $509 million non-cash lease reclassification gain ?Reported adjusted EBITDA attributable to MPLX of $1,471 million, up 6% year over year ?Generated $1,039 million in net cash provided by operating activities ?Returned $935 million of capital to unith

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 ☐ TRANSITION REPO

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file numbe

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 11, 2022 MPLX LP (Exact na

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) October 11, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

A MESSAGE FROM MICHAEL J. HENNIGAN

Exhibit 99.1 A MESSAGE FROM MICHAEL J. HENNIGAN October 11, 2022 Dear Colleagues and Unitholders, This past April, I shared with you that I had been diagnosed with throat cancer and would be undergoing treatment. Today, I want to share a very positive update. I completed the seven-week radiation and chemotherapy treatment protocol for this condition a few months ago. As is routine for this type of

MPLX / MPLX LP / Marathon Petroleum Corp - SCHEDULE 13D/A AMENDMENT NO. 16 Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Amendment No. 16) Under the Securities Exchange Act of 1934 MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securities) 55336V100 (CUSIP Number) Molly R. Benson Vice President, Chief Securities, Governance & Compliance Officer and Corporate Secretary Marathon Petr

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 22, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IR

Twenty-Sixth Supplemental Indenture, dated as of August 11, 2022, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)

Exhibit 4.1 TWENTY-SIXTH SUPPLEMENTAL INDENTURE THIS TWENTY-SIXTH SUPPLEMENTAL INDENTURE, dated as of August 11, 2022 (this ?Supplemental Indenture?), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the ?Partnership?), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the ?Trustee?). WITNESSE

Underwriting Agreement, dated as of August 8, 2022, by and among the Issuer, MPLX GP LLC, the general partner of the Issuer, and each of Barclays Capital Inc., Mizuho Securities USA LLC and Wells Fargo Securities, LLC, acting as representatives of the several underwriters named therein

EX-1.1 2 d375931dex11.htm EX-1.1 Exhibit 1.1 EXECUTION VERSION MPLX LP as Issuer, and MPLX GP LLC as General Partner, $1,000,000,000 4.950% SENIOR NOTES DUE 2032 UNDERWRITING AGREEMENT August 8, 2022 August 8, 2022 To the Representatives named in Schedule I hereto for the Underwriters named in Schedule II hereto Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the “Partnership”), pro

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 11, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IR

MPLX LP $1,000,000,000 4.950% Senior Notes due 2032

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-248443 PROSPECTUS SUPPLEMENT (To Prospectus Dated August 27, 2020) MPLX LP $1,000,000,000 4.950% Senior Notes due 2032 MPLX LP, or ?MPLX,? ?we? or ?us,? is offering $1,000,000,000 aggregate principal amount of 4.950% Senior Notes due 2032, which we refer to as the ?notes.? We will pay interest on the notes semi-annually in arr

Calculation of Filing Fee Table (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maxim

Exhibit 107 Calculation of Filing Fee Table 424(b)(5) (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee(1) Carry Forward Form Type Carry Forward File Number Carry Forward Initial Effective Date Filing Fee Previously Paid In Connection with Unsold Securities to be Carried Forward Debt 4.

MPLX LP Final Pricing Term Sheet August 8, 2022 $1,000,000,000 4.950% Senior Notes due 2032 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2 (stable) / BBB (stable) / BBB (stable) Net proceeds (before expenses) to the Issuer: $987,830,

Filed Pursuant to Rule 433 Registration No. 333-248443 August 8, 2022 Supplementing the Preliminary Prospectus Supplement dated August 8, 2022 (To Prospectus dated August 27, 2020) MPLX LP Final Pricing Term Sheet August 8, 2022 $1,000,000,000 4.950% Senior Notes due 2032 Issuer: MPLX LP Expected Ratings (Moody?s / S&P / Fitch)*: Baa2 (stable) / BBB (stable) / BBB (stable) Net proceeds (before exp

Subject to Completion Preliminary Prospectus Supplement dated August 8, 2022

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-248443 The information contained in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell the securities and are not soliciting an offer to buy the senior notes offered hereby in any jurisdiction where the offer

MPLX LP Reports Second-Quarter 2022 Financial Results

Exhibit 99.1 MPLX LP Reports Second-Quarter 2022 Financial Results ?Reported second-quarter net income attributable to MPLX of $875 million and adjusted EBITDA attributable to MPLX of $1.5 billion ?Generated $1.5 billion in net cash provided by operating activities ?Returned over $750 million of capital to unitholders through distributions and unit repurchases ?Announces incremental $1 billion rep

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 2, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 ☐ TRANSITION REPORT PU

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001

Seventh Amendment to Third Amended and Restated Terminal Services Agreement, dated March 1, 2017, between MPLX Terminals LLC and Marathon Petroleum Company LP

Exhibit 10.3 Seventh Amendment to the Third Amended and Restated Terminal Services Agreement This Seventh Amendment to the Third Amended and Restated Terminal Services Agreement ("Amendment") is dated as of May 20,2022, by and between Marathon Petroleum Company LP, a Delaware limited partnership with an address of 539 South Main Street, Findlay, Ohio 45840 ("MPC"), and MPLX Terminals LLC, a Delawa

Entry into a Material Definitive Agreement, Termination of a Material Definitive Agreement, Financial Statements and Exhibits, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 7, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS E

Revolving Credit Agreement, dated as of July 7, 2022, by and among MPLX LP, as borrower, Wells Fargo Bank, National Association, as administrative agent, each of Wells Fargo Securities, LLC, JPMorgan Chase Bank, N.A., Barclays Bank PLC, BofA Securities, Inc., Citibank, N.A., Mizuho Bank, Ltd., MUFG Bank, Ltd., RBC Capital Markets and TD Securities (USA) LLC, as joint lead arrangers and joint bookrunners, JPMorgan Chase Bank, N.A., as syndication agent, each of Bank of America, N.A., Barclays Bank PLC, Citibank, N.A., Mizuho Bank, Ltd., MUFG Bank, Ltd., Royal Bank of Canada and The Toronto-Dominion Bank, New York Branch, as documentation agents, and the other lenders and issuing banks that are parties thereto

Exhibit 10.1 REVOLVING CREDIT AGREEMENT dated as of July 7, 2022, among MPLX LP, the LENDERS from time to time party hereto and WELLS FARGO BANK, NATIONAL ASSOCIATION, as Administrative Agent WELLS FARGO SECURITIES, LLC, JPMORGAN CHASE BANK, N.A., BARCLAYS BANK PLC, BOFA SECURITIES, INC., CITIBANK, N.A., MIZUHO BANK, LTD., MUFG BANK, LTD., RBC CAPITAL MARKETS1 and TD SECURITIES (USA) LLC, as Joint

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) June 30, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

Master Amendment to Transportation Services Agreements, dated as of June 30, 2022, by and among Marathon Petroleum Company LP, Marathon Petroleum Supply and Trading LLC, Marathon Pipe Line LLC and Ohio River Pipe Line LLC

Exhibit 10.1 MASTER AMENDMENT TO TRANSPORTATION SERVICE AGREEMENTS This Master Amendment to Transportation Service Agreements (?Amendment?) is made and entered into as of June 30, 2022 (?Effective Date?) by and between Marathon Petroleum Company LP, a Delaware limited partnership (?MPC?), Marathon Petroleum Supply and Trading LLC, a Delaware limited liability company (?MPST?), Marathon Pipe Line L

MPLX LP Reports First-Quarter 2022 Financial Results

Exhibit 99.1 MPLX LP Reports First-Quarter 2022 Financial Results ?Reported first-quarter net income attributable to MPLX of $825 million and adjusted EBITDA attributable to MPLX of $1.4 billion ?Generated $1.1 billion in net cash provided by operating activities ?Returned over $850 million in capital to unitholders through distributions and unit repurchases ?Expanded our methane emissions intensi

CEO Phantom Unit Award Agreement, as Amended

Exhibit 10.2 MPLX LP 2018 INCENTIVE COMPENSATION PLAN PHANTOM UNIT AWARD AGREEMENT (as amended effective January 25, 2022) MPLX OFFICER As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan (the ?Plan?), MPLX GP LLC, a Delaware limited liability company (the ?Company?), the general partner of MPLX LP, a Delaware limited partnership (the ?Partnership?) has gran

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 3, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Em

Form of 2022 MPLX Phantom Unit Award Agreement

Exhibit 10.1 MPLX LP PHANTOM UNIT AWARD AGREEMENT As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan, as amended (the ?Plan?), MPLX GP LLC, a Delaware limited liability company (the ?Company?), the general partner of MPLX LP, a Delaware limited partnership (the ?Partnership?) has granted to {Participant Name} (the ?Participant?), an Employee and/or Officer

CEO Performance Unit Award Agreement – 2020-2022 Performance Cycle, as Amended

Exhibit 10.3 MPLX LP 2018 INCENTIVE COMPENSATION PLAN PERFORMANCE UNIT AWARD AGREEMENT 2020-2022 PERFORMANCE CYCLE MPLX OFFICER (amended effective January 25, 2022) As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan (the ?Plan?), MPLX GP LLC, a Delaware limited liability company (the ?Company?), the general partner of MPLX LP, a Delaware limited partnership

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 ☐ TRANSITION REPORT P

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 00

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 21, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

EX-99.1

Exhibit 99.1 A MESSAGE FROM MICHAEL J. HENNIGAN April 21, 2022 Dear Colleagues and Unitholders, Our team has navigated many challenges. We addressed them head on and have been very successful. Today, I am confronted with a personal challenge. Through a recent health physical, it was discovered that I have a tumor in my throat. The good news is that it was caught early and is curable. Tests have co

Twenty-Fifth Supplemental Indenture, dated as of March 14, 2022, by and between the Issuer and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Note)

Exhibit 4.1 TWENTY-FIFTH SUPPLEMENTAL INDENTURE THIS TWENTY-FIFTH SUPPLEMENTAL INDENTURE, dated as of March 14, 2022 (this ?Supplemental Indenture?), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the ?Partnership?), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the ?Trustee?). WITNESSET

Calculation of Filing Fee Table (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maxim

Exhibit 107 Calculation of Filing Fee Table 424(b)(5) (Form Type) MPLX LP (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee(1) Carry Forward Form Type Carry Forward File Number Carry Forward Initial Effective Date Filing Fee Previously Paid In Connection with Unsold Securities to be Carried Forward Debt 4.

MPLX LP $1,500,000,000 4.950% Senior Notes due 2052

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-248443 PROSPECTUS SUPPLEMENT (To Prospectus Dated August 27, 2020) MPLX LP $1,500,000,000 4.950% Senior Notes due 2052 MPLX LP, or ?MPLX,? ?we? or ?us,? is offering $1,500,000,000 aggregate principal amount of 4.950% Senior Notes due 2052, which we refer to as the ?notes.? We will pay interest on the notes semi-annually in arr

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 14, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

Underwriting Agreement, dated as of March 10, 2022, by and among the Issuer, MPLX GP LLC, the general partner of the Issuer, and each of Citigroup Global Markets Inc., RBC Capital Markets, LLC and TD Securities (USA) LLC, acting as representatives of the several underwriters named therein

Exhibit 1.1 EXECUTION VERSION MPLX LP as Issuer, and MPLX GP LLC as General Partner, $1,500,000,000 4.950% SENIOR NOTES DUE 2052 UNDERWRITING AGREEMENT March 10, 2022 March 10, 2022 To the Representatives named in Schedule I hereto for the Underwriters named in Schedule II hereto Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the ?Partnership?), proposes to issue and sell to the se

MPLX LP Final Pricing Term Sheet March 10, 2022 $1,500,000,000 4.950% Senior Notes due 2052 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2 (stable) / BBB (stable) / BBB (stable) Net proceeds (before expenses) to the Issuer: $1,471,60

Filed Pursuant to Rule 433 Registration No. 333-248443 March 10, 2022 Supplementing the Preliminary Prospectus Supplement dated March 10, 2022 (To Prospectus dated August 27, 2020) MPLX LP Final Pricing Term Sheet March 10, 2022 $1,500,000,000 4.950% Senior Notes due 2052 Issuer: MPLX LP Expected Ratings (Moody?s / S&P / Fitch)*: Baa2 (stable) / BBB (stable) / BBB (stable) Net proceeds (before exp

Subject to Completion Preliminary Prospectus Supplement dated March 10, 2022

Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-248443 The information contained in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell the securities and are not soliciting an offer to buy the senior notes offered hereby in any jurisdiction where the offer

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K (Mark One) ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-357

Power of Attorney of Directors and Officers of MPLX GP LLC

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned officers and directors of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the ?Registrant?), does hereby constitute and appoint Michael J. Hennigan, John J. Quaid and Kelly D. Wright, and each of them, as his or her true and lawful attorney or at

List of Subsidiaries

Exhibit 21.1 MPLX LP LIST OF SUBSIDIARIES as of December 31, 2021 Name of Subsidiary Jurisdiction of Organization/Incorporation Andeavor Field Services LLC Delaware Andeavor Gathering I LLC Delaware Andeavor Logistics CD LLC Delaware Andeavor Logistics GP LLC Delaware Andeavor Logistics LP Delaware * Andeavor Logistics Rio Pipeline LLC Delaware Andeavor Midstream Partners GP LLC Delaware Andeavor

MPLX / MPLX LP / Blackstone Group Management L.L.C. - SC 13G/A Passive Investment

SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* MPLX LP (Name of Issuer) Common Units Representing Limited Partnership Interests (Title of Class of Securities) 55336V100 (CUSIP Number) December 31, 2021 (Date of Event which Requires Filing of this Statement) Check the appropriate box to desig

MPLX LP Reports Fourth-Quarter and Full-Year 2021 Financial Results

Exhibit 99.1 MPLX LP Reports Fourth-Quarter and Full-Year 2021 Financial Results ?Reported fourth quarter net income attributable to MPLX of $830 million and full-year net income of $3.1 billion ?Reported fourth quarter adjusted EBITDA attributable to MPLX of $1.4 billion and full-year adjusted EBITDA of $5.6 billion ?Generated $4.9 billion in net cash provided by operating activities for the full

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 2, 2022 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 29, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (

MPLX LP Reports Third-Quarter 2021 Financial Results

MPLX LP Reports Third-Quarter 2021 Financial Results ?Reported net income attributable to MPLX of $802 million and adjusted EBITDA attributable to MPLX of $1.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 2, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commis

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 ☐ TRANSITION REPO

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file numbe

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 2, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

Fourth Amendment to the Terminal Services Agreement, dated as of July 31, 2021, by and between the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto

Exhibit 10.1 FOURTH AMENDMENT TO TERMINAL SERVICES AGREEMENT This Fourth Amendment to Terminal Services Agreement (this "Amendment") is dated as of July 31, 2021 (the ?Amendment Date?), by and between, with respect to each respective Terminal set forth on Schedule I, the party identified as "Customer" with respect to such respective Terminal as set forth on Schedule I (such party, as applicable to

MPLX LP Reports Third-Quarter 2021 Financial Results

MPLX LP Reports Third-Quarter 2021 Financial Results ?Reported net income attributable to MPLX of $802 million and adjusted EBITDA attributable to MPLX of $1.

MPLX / MPLX LP / Marathon Petroleum Corp - SC 13D/A AMENDMENT 15 Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Amendment No. 15) Under the Securities Exchange Act of 1934 MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securities) 55336V100 (CUSIP Number) Molly R. Benson Vice President, Chief Securities, Governance & Compliance Officer and Corporate Secretary Marathon Petr

the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto

Exhibit 10.2 SECOND AMENDMENT TO TERMINAL SERVICES AGREEMENT This Second Amendment to Terminal Services Agreement (this "Amendment") is dated as of May 30, 2021 (the ?Amendment Date?), by and between, with respect to each respective Terminal set forth on Schedule I, the party identified as "Customer" with respect to such respective Terminal as set forth on Schedule I (such party, as applicable to

dated as of April 30, 2021, by and among the MPLX LP and Marathon Petroleum Corporation subsi

Exhibit 10.1 FIRST AMENDMENT TO TERMINAL SERVICES AGREEMENT This First Amendment to Terminal Services Agreement (this "Amendment") is dated as of April 30, 2021 (the ?Amendment Date?), by and between, with respect to each respective Terminal set forth on Schedule I, the party identified as "Customer" with respect to such respective Terminal as set forth on Schedule I (such party, as applicable to

MPLX LP Announces Retirement of Pamela K.M. Beall; John J. Quaid Named Executive Vice President and Chief Financial Officer of MPLX GP LLC

MPLX LP Announces Retirement of Pamela K.M. Beall; John J. Quaid Named Executive Vice President and Chief Financial Officer of MPLX GP LLC FINDLAY, Ohio, Aug. 4, 2021 ? MPLX LP (NYSE: MPLX) today announced that Pamela K.M. Beall, Executive Vice President and Chief Financial Officer of MPLX GP LLC, will retire later this year after more than 25 years of service with sponsor Marathon Petroleum (NYSE

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 4, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

MPLX LP Reports Second-Quarter 2021 Financial Results

MPLX LP Reports Second-Quarter 2021 Financial Results ?Reported net income attributable to MPLX of $706 million and adjusted EBITDA attributable to MPLX of $1.

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) July 30, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 ☐ TRANSITION REPORT PU

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001

May 14, 2021

May 14, 2021 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance Office of Energy & Transportation 100 F Street, NE Washington, D.C. 20549 RE: MPLX LP Form 10-K for the Fiscal Year Ended December 31, 2020 Filed February 26, 2021 File No. 001-35714 Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the ?Company?), is in receipt of the comment of the staff (

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 00

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 4, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Em

MPLX LP Reports First-Quarter 2021 Financial Results

MPLX LP Reports First-Quarter 2021 Financial Results ?Reported net income attributable to MPLX of $739 million and adjusted EBITDA attributable to MPLX of $1.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 20, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

Annual Report - 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-35714 MPLX LP (Ex

Form of 2021 MPLX Phantom Unit Award Agreement

Exhibit 10.105 MPLX LP 2018 INCENTIVE COMPENSATION PLAN PHANTOM UNIT AWARD AGREEMENT MPLX CEO, DESIGNATED POSITIONS, & EXECUTIVE RESOURCES As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan (the ?Plan?), MPLX GP LLC, a Delaware limited liability company (the ?Company?), the general partner of MPLX LP, a Delaware limited partnership (the ?Partnership?) has g

Amendment to Amended and Restated Transportation Services Agreement, executed as of February 15, 2021, by and between Marathon Petroleum Company LP and Hardin Street Marine LLC

Exhibit 10.106 Second Amendment To The Amended and Restated Transportation Services Agreement Effective January 1, 2015 Between Marathon Petroleum Company LP and Hardin Street Marine LLC THIS SECOND AMENDMENT (?Amendment?) by and between Hardin Street Marine LLC (?HSM?) and Marathon Petroleum Company LP (?MPC?) is effective as of the 1st day of January, 2021 (which shall be the ?Effective Date? fo

Exhibit 4.3

Exhibit 4.3 DESCRIPTION OF THE REGISTRANT?S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 MPLX LP (?MPLX?), a master limited partnership controlled by Marathon Petroleum Corporation (?MPC?), had one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended (the ?Exchange Act?): common units representing limited partner

Power of Attorney of Directors and Officers of MPLX GP LLC

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned officers and directors of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the ?Registrant?), does hereby constitute and appoint Michael J. Hennigan, Pamela K.M. Beall and C. Kristopher Hagedorn, and each of them, as his or her true and lawful att

HSM Services Agreement, dated as of October 1, 2020, by and among Marathon Petroleum Company LP, Marathon Petroleum Trading and Supply LLC and Hardin Street Marine LLC

Exhibit 10.104 HSM SERVICES AGREEMENT THIS HSM SERVICES AGREEMENT (?Agreement?) is made and entered into effective October 1, 2020 by and among MARATHON PETROLEUM COMPANY LP (?MPCLP?), MARATHON PETROLEUM SUPPLY AND TRADING LLC (?MPST?), and HARDIN STREET MARINE LLC (?HSM?) (each a ?Party? and together the ?Parties?). WHEREAS, effective October 1, 2020 (the ?Transition Date?), MPST will become MPCL

List of Subsidiaries

EX-21.1 6 mplx-20201231xex211.htm EX-21.1 Exhibit 21.1 MPLX LP LIST OF SUBSIDIARIES as of December 31, 2020 Name of Subsidiary Jurisdiction of Organization/Incorporation Andeavor Field Services LLC Delaware Andeavor Gathering I LLC Delaware Andeavor Logistics CD LLC Delaware Andeavor Logistics GP LLC Delaware Andeavor Logistics LP Delaware * Andeavor Logistics Rio Pipeline LLC Delaware Andeavor Mi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securiti

SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securities) 55336V100 (CUSIP Number) December 31, 2020 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 1, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

Sixth Amended and Restated Agreement of Limited Partnership of MPLX LP, dated as of February 1, 2021

EX-3.1 2 exhibit31sixthamendedlpagr.htm EX-3.1 Exhibit 3.1 SIXTH AMENDED AND RESTATED AGREEMENT OF LIMITED PARTNERSHIP OF MPLX LP A Delaware Limited Partnership Dated as of February 1, 2021 Table of Contents (continued) Page ARTICLE I DEFINITIONS 2 Section 1.1 Definitions 2 Section 1.2 Construction 22 ARTICLE II ORGANIZATION 22 Section 2.1 Formation 22 Section 2.2 Name 22 Section 2.3 Registered Of

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 2, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

MPLX LP Reports Fourth Quarter and Full-Year 2020 Financial Results

MPLX LP Reports Fourth Quarter and Full-Year 2020 Financial Results •Reported fourth quarter net income attributable to MPLX of $691 million and full-year net loss of $720 million (includes non-cash impairment charges of $3.

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) February 1, 2021 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

JOINT FILING AGREEMENT

EX-99.1 2 ex991jointfilingagreement.htm EX-99.1 Exhibit 99.1 JOINT FILING AGREEMENT The undersigned hereby agree that they are filing this statement jointly pursuant to Rule 13d-1(k)(1). Each of them is responsible for the timely filing of such Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information concerning such person contained therein; but none of the

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Amendment No. 14) Under the Securities Exchange Act of 1934 MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Amendment No. 14) Under the Securities Exchange Act of 1934 MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securities) 55336V100 (CUSIP Number) Molly R. Benson Vice President, Chief Securities, Governance & Compliance Officer and Corporate Secretary Marathon Petr

Sixth Amendment to Third Amended and Restated Terminal Services Agreement, dated March 1, 2017, between MPLX Terminals LLC and Marathon Petroleum Company LP

Exhibit 10.2 Sixth Amendment to the Third Amended and Restated Terminal Services Agreement This Sixth Amendment to the Third Amended and Restated Terminal Services Agreement ("Amendment") is dated September 1, 2020 by and between Marathon Petroleum Company LP, a Delaware limited partnership with an address of 539 South Main Street, Findlay, Ohio 45840 ("MPC"), and MPLX Terminals LLC, a Delaware li

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file numbe

Notice of and Consent to Assignment, effective October 1, 2020, by and among Marathon Petroleum Company LP, Marathon Petroleum Trading and Supply LLC and Hardin Street Transportation LLC

Exhibit 10.4 September 28, 2020 Via Email and US Mail Hardin Street Transportation LLC Attn: President 200 E. Hardin Street Findlay, OH 45840 Effective October 1, 2020, Marathon Petroleum Company LP (“MPC”) will be transitioning its crude procurement and logistics functions to Marathon Petroleum Supply and Trading LLC (“MPST”). This letter documents the intent of MPC, MPST and Hardin Street Transp

Amendment to Amended and Restated Transportation Services Agreement, executed as of September 10, 2020, by and between Marathon Petroleum Company LP and Hardin Street Marine LLC

Exhibit 10.3 FIRST AMENDMENT TO THE AMENDED AND RESTATED TRANSPORTATION SERVICES AGREEMENT THIS FIRST AMENDMENT (“Amendment”) TO THE AMENDED AND RESTATED TRANSPORTATION SERVICES AGREEMENT is effective this June 1, 2020 by and between Marathon Petroleum Company LP, a Delaware limited partnership (“MPC”) and Hardin Street Marine LLC, a Delaware limited liability company (“HSM”). MPC and HSM may be r

Notice of and Consent to Assignment, effective October 1, 2020, by and among Marathon Petroleum Company LP, Marathon Petroleum Trading and Supply LLC and Marathon Pipe Line LLC

Exhibit 10.5 September 28, 2020 Via Email and US Mail Marathon Pipe Line LLC Attn: President 539 S. Main Street Findlay, OH 45840 Dear Sir: Effective October 1, 2020, Marathon Petroleum Company LP (“MPC”) will be transitioning its crude procurement and logistics functions to Marathon Petroleum Supply and Trading LLC (“MPST”). To make this transition as seamless and efficient as possible, MPC will

Notice of and Consent to Assignment, effective October 1, 2020, by and among Marathon Petroleum Company LP, Marathon Petroleum Trading and Supply LLC and Marathon Pipe Line LLC (Commingled)

Exhibit 10.6 September 28, 2020 Via Email and US Mail Marathon Pipe Line LLC Attn: President 539 S. Main Street Findlay, OH 45840 Effective October 1, 2020, Marathon Petroleum Company LP (“MPC”) will be transitioning its crude procurement and logistics functions to Marathon Petroleum Supply and Trading LLC (“MPST”). This letter documents the intent of MPC, MPST and Marathon Pipe Line LLC (“MPL”) w

Terminal Services Agreement, dated as of November 1, 2020, by and among the MPLX LP and Marathon Petroleum Corporation subsidiaries party thereto.

Exhibit 10.1 TERMINAL SERVICES AGREEMENT This Terminal Services Agreement ("Agreement") is dated November 1, 2020 by and between, with respect to each respective Terminal set forth on Schedule I, the party identified as “Customer” with respect to such respective Terminal as set forth on Schedule I (such party, as applicable to the respective Terminal, a “Customer”), and the party identified as “Te

Entry into a Material Definitive Agreement, Financial Statements and Exhibits - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 1, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

Financial Statements and Exhibits, Results of Operations and Financial Condition - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) November 2, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (I

MPLX LP Reports Third-Quarter 2020 Financial Results

MPLX LP Reports Third-Quarter 2020 Financial Results • Reported net income attributable to MPLX of $665 million, including a charge of $36 million, and adjusted EBITDA attributable to MPLX of $1.

Costs Associated with Exit or Disposal Activities - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) September 29, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTE

EX-25.2 7 ex-2522020.htm EXHIBIT 25.2 Exhibit 25.2 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) ¨ The Bank of New York Mellon Trust Company, N.A. (Exact name of tr

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTE

Exhibit 25.1 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) ¨ The Bank of New York Mellon Trust Company, N.A. (Exact name of trustee as specified in its charter) N/A

- S-3ASR

Table of Contents As filed with the Securities and Exchange Commission on August 27, 2020 Registration No.

POWER OF ATTORNEY

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned directors and officers of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the “Registrant”), does hereby constitute and appoint Michael J. Hennigan, Pamela K.M. Beall and C. Kristopher Hagedorn, or any of them, each acting alone, as the true and

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 17, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IR

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 18, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IR

MPLX LP as Issuer, and MPLX GP LLC as General Partner, $1,500,000,000 1.750% SENIOR NOTES DUE 2026 $ 1,500,000,000 2.650% SENIOR NOTES DUE 2030 UNDERWRITING AGREEMENT

Exhibit 1.1 MPLX LP as Issuer, and MPLX GP LLC as General Partner, $1,500,000,000 1.750% SENIOR NOTES DUE 2026 $ 1,500,000,000 2.650% SENIOR NOTES DUE 2030 UNDERWRITING AGREEMENT August 11, 2020 August 11, 2020 To the Representatives named in Schedule I hereto for the Underwriters named in Schedule II hereto Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the “Partnership”), propose

Twenty-Third Supplemental Indenture, dated as of August 18, 2020, by and between MPLX LP and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Notes)

Exhibit 4.1 TWENTY-THIRD SUPPLEMENTAL INDENTURE THIS TWENTY-THIRD SUPPLEMENTAL INDENTURE, dated as of August 18, 2020 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the “Trustee”). WITNESSE

Twenty-Fourth Supplemental Indenture, dated as of August 18, 2020, by and between MPLX LP and The Bank of New York Mellon Trust Company, N.A., as Trustee (including Form of Notes)

Exhibit 4.2 TWENTY-FOURTH SUPPLEMENTAL INDENTURE THIS TWENTY-FOURTH SUPPLEMENTAL INDENTURE, dated as of August 18, 2020 (this “Supplemental Indenture”), is between MPLX LP, a limited partnership duly formed and existing under the laws of the State of Delaware (the “Partnership”), and The Bank of New York Mellon Trust Company, N.A., a national banking association, as trustee (the “Trustee”). WITNES

CALCULATION OF REGISTRATION FEE Title of each Class of Securities to be Registered Amount to be Registered Proposed Maximum Offering Price Proposed Maximum Aggregate Offering Price Amount of Registration Fee (1) 1.750% Notes due 2026 $1,500,000,000 9

Form 424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-220267 CALCULATION OF REGISTRATION FEE Title of each Class of Securities to be Registered Amount to be Registered Proposed Maximum Offering Price Proposed Maximum Aggregate Offering Price Amount of Registration Fee (1) 1.750% Notes due 2026 $1,500,000,000 99.785% $1,496,775,000 $194,281.40 2.650% Notes due 2030 $1,5

MPLX LP Final Pricing Terms August 11, 2020 $1,500,000,000 1.750% Senior Notes due 2026 $1,500,000,000 2.650% Senior Notes due 2030 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2/BBB/BBB Net proceeds (before expenses) to the Issuer:

FWP Filed Pursuant to Rule 433 Registration No. 333-220267 August 11, 2020 Supplementing the Preliminary Prospectus Supplement dated August 11, 2020 (To Prospectus dated August 30, 2017) MPLX LP Final Pricing Terms August 11, 2020 $1,500,000,000 1.750% Senior Notes due 2026 $1,500,000,000 2.650% Senior Notes due 2030 Issuer: MPLX LP Expected Ratings (Moody’s / S&P / Fitch)*: Baa2/BBB/BBB Net proce

Subject to Completion Preliminary Prospectus Supplement dated August 11, 2020

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-220267 The information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell the notes and are not soliciting an offer to buy the notes in any jurisdiction where the offer or sale is not permitted. Subj

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 10, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IR

MPLX / MPLX LP / Marathon Petroleum Corp - SCHEDULE 13D/A (AMENDMENT NO. 13) Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D/A (Amendment No. 13) Under the Securities Exchange Act of 1934 MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securities) 55336V100 (CUSIP Number) Molly R. Benson Vice President, Chief Securities, Governance & Compliance Officer and Corporate Secretary Marathon Petr

MPLX LP Reports Second-Quarter 2020 Financial Results

EX-99.1 2 mplxq22020earningsrele.htm EXHIBIT 99.1 MPLX LP Reports Second-Quarter 2020 Financial Results • Reported net income attributable to MPLX of $648 million and adjusted EBITDA attributable to MPLX of $1.2 billion • Generated $1.1 billion in net cash provided by operating activities and reported distribution coverage of 1.39x • Maintained quarterly distribution of $0.6875 per common unit • O

Redemption Agreement, dated July 31, 2020, between MPLX LP and Western Refining Southwest, Inc.

EX-10.1 2 mplx-2020630xex101.htm EXHIBIT 10.1 Exhibit 10.1 REDEMPTION AGREEMENT between MPLX LP and Western Refining Southwest, Inc. Dated July 31, 2020 REDEMPTION AGREEMENT THIS REDEMPTION AGREEMENT (this “Agreement”) is entered into on July 31, 2020 (the “Execution Date”), by and between MPLX LP, a Delaware limited partnership (“MPLX”), and Western Refining Southwest Inc., an Arizona corporation

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) August 3, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

JOINT FILING AGREEMENT

Exhibit A Exhibit A JOINT FILING AGREEMENT Pursuant to and in accordance with the Securities Exchange Act of 1934, as amended, and the rules and regulations thereunder (the “Exchange Act”) the undersigned hereby agree to the joint filing of The Blackstone Group Inc.

MPLX / MPLX LP / Blackstone Group Management L.L.C. - SC 13G Passive Investment

SC 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* MPLX LP (Name of Issuer) Common Units Representing Limited Partner Interests (Title of Class of Securities) 55336V100 (CUSIP Number) July 6, 2020 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rul

Form of 2020 MPLX LP Phantom Unit Award Agreement - MPLX Officer

Exhibit 10.1 MPLX LP 2018 INCENTIVE COMPENSATION PLAN PHANTOM UNIT AWARD AGREEMENT MPLX OFFICER As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to [NAME] (the “Participant”), an of

Form of MPLX LP Performance Unit Award Agreement 2020-2022 Performance Cycle - MPC Officer

EXHIBIT 10.4 MPLX LP 2018 INCENTIVE COMPENSATION PLAN PERFORMANCE UNIT AWARD AGREEMENT 2020-2022 PERFORMANCE CYCLE MPC OFFICER As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to [N

Quarterly Report - 10-Q

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2020 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 00

Form of 2020 MPLX LP Phantom Unit Award Agreement - MPC Officer

EXHIBIT 10.2 MPLX LP 2018 INCENTIVE COMPENSATION PLAN PHANTOM UNIT AWARD AGREEMENT MPC OFFICER As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to [NAME] (the “Participant”), an off

Form of 2020 MPLX LP Performance Unit Award Agreement 2020-2022 Performance Cycle - MPLX Officer

Exhibit 10.3 MPLX LP 2018 INCENTIVE COMPENSATION PLAN PERFORMANCE UNIT AWARD AGREEMENT 2020-2022 PERFORMANCE CYCLE MPLX OFFICER As evidenced by this Award Agreement and under the MPLX LP 2018 Incentive Compensation Plan (the “Plan”), MPLX GP LLC, a Delaware limited liability company (the “Company”), the general partner of MPLX LP, a Delaware limited partnership (the “Partnership”) has granted to [

MPLX LP Reports First-Quarter 2020 Financial Results

EX-99.1 2 mplxq12020earningsrele.htm EXHIBIT 99.1 MPLX LP Reports First-Quarter 2020 Financial Results • Reported net loss attributable to MPLX of $2.7 billion; includes non-cash impairment charges of $3.4 billion primarily related to goodwill, equity method investments, and long-lived assets • Reported adjusted EBITDA attributable to MPLX of $1.3 billion • Generated $1.0 billion in net cash provi

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) May 5, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Em

Board of MPLX LP general partner elects Michael J. Hennigan as chairman

Board of MPLX LP general partner elects Michael J. Hennigan as chairman FINDLAY, Ohio, April 30, 2020 – The board of directors of the general partner of MPLX LP (NYSE: MPLX) has elected Michael J. Hennigan as chairman, succeeding retiring chairman Gary R. Heminger. Hennigan’s appointment became effective April 29. Hennigan is president and chief executive officer of the general partner of MPLX LP,

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) April 28, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

MPLX LP Offers To Exchange All of the outstanding restricted 6.250% Senior Notes Due 2022 Issued on September 23, 2019 For newly issued and registered 6.250% Senior Notes Due 2022 All of the outstanding restricted 3.500% Senior Notes Due 2022 Issued

Filed Pursuant to Rule 424(b)(3) Registration No. 333-237317 PROSPECTUS MPLX LP Offers To Exchange All of the outstanding restricted 6.250% Senior Notes Due 2022 Issued on September 23, 2019 For newly issued and registered 6.250% Senior Notes Due 2022 All of the outstanding restricted 3.500% Senior Notes Due 2022 Issued on September 23, 2019 For newly issued and registered 3.500% Senior Notes Due

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April 16, 2020 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance Office of Energy & Transportation 100 F Street, NE Washington, D.C. 20549 RE: MPLX LP Registration Statement on Form S-4 Filed March 20, 2020 File No. 333-237317 Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the “Company”), is in receipt of the comment of the staff (the “Staff”) of the

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April 16, 2020 VIA EDGAR CORRESPONDENCE U.S. Securities and Exchange Commission Division of Corporation Finance Office of Energy & Transportation 100 F Street, NE Washington, DC 20549 Attention: Karina Dorin, Staff Attorney Re: MPLX LP Registration Statement on Form S-4 Filed March 20, 2020 File No. 333-237317 Ladies and Gentlemen: On behalf of MPLX LP (the “Company”), the undersigned hereby reque

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April 9, 2020 VIA EDGAR U.S. Securities and Exchange Commission Division of Corporation Finance Office of Energy & Transportation 100 F Street, NE Washington, D.C. 20549 RE: MPLX LP Registration Statement on Form S-4 Filed March 20, 2020 File No. 333-237317 Ladies and Gentlemen: MPLX LP, a Delaware limited partnership (the “Company,” “we,” “us,” or “our”), is in receipt of the comment of the staff

POWER OF ATTORNEY

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned directors and officers of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the "Registrant"), does hereby constitute and appoint Michael J. Hennigan, Pamela K.M. Beall and C. Kristopher Hagedorn, and each of them acting individually, as the true a

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T‑1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTE

Exhibit 25.1 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T‑1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE CHECK IF AN APPLICATION TO DETERMINE ELIGIBILITY OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) [ ] THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A. (Exact name of trustee as specified in its charter) N

MPLX / MPLX LP S-4 - - S-4

As Filed with the Securities and Exchange Commission on March 20, 2020 Registration No.

Marathon Petroleum Corp. Board Concludes Review of Midstream Business

EX-99.1 2 ex991midrlse.htm EXHIBIT 99.1 Marathon Petroleum Corp. Board Concludes Review of Midstream Business FINDLAY, Ohio, March 18, 2020 – Marathon Petroleum Corporation (NYSE: MPC) today announced the unanimous decision of its Board of Directors to maintain MPC’s current midstream structure, with the company remaining the general partner of MPLX LP (NYSE: MPLX). “Today’s announcement concludes

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported) March 18, 2020 MPLX LP (Exact name of registrant as specified in its charter) Delaware 001-35714 27-0005456 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

Fifth Amendment to Third Amended and Restated Terminal Services Agreement, dated March 1, 2017, between MPLX Terminals LLC and Marathon Petroleum Company LP

Exhibit 10.103 Fifth Amendment to the Third Amended and Restated Terminal Services Agreement This Fifth Amendment to the Third Amended and Restated Terminal Services Agreement ("Amendment") is dated December 13, 2019 by and between Marathon Petroleum Company LP, a Delaware limited partnership with an address of 539 South Main Street, Findlay, Ohio 45840 ("MPC"), and MPLX Terminals LLC, a Delaware

First Amendment to the MPLX 2018 Incentive Compensation Plan

Exhibit 10.75 FIRST AMENDMENT TO THE MPLX LP 2018 INCENTIVE COMPENSATION PLAN WHEREAS, MPLX GP LLC, a Delaware limited liability company (the “Company”), sponsors and maintains the MPLX LP 2018 Incentive Compensation Plan, as originally effective March 15, 2018 (the “Plan”); WHEREAS, pursuant to paragraph 7 of the Plan, the Company’s Board of Directors (the “Board”) has the authority to amend the

Annual Report - 10-K

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2019 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-35714 MPLX LP (Ex

Description of Securities

Exhibit 4.33 DESCRIPTION OF THE REGISTRANT’S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 As of February 28, 2020, MPLX LP (“MPLX”), a master limited partnership controlled by Marathon Petroleum Corporation (“MPC”), had one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended: common units representing limited par

List of Subsidiaries

Exhibit 21.1 MPLX LP LIST OF SUBSIDIARIES as of December 31, 2019 Name of Subsidiary Jurisdiction of Organization/Incorporation Andeavor Field Services LLC Delaware Andeavor Gathering I LLC Delaware Andeavor Logistics CD LLC Delaware Andeavor Logistics GP LLC Delaware Andeavor Logistics LP Delaware Andeavor Logistics Rio Pipeline LLC Delaware Andeavor Midstream Partners GP LLC Delaware Andeavor Mi

Fourth Amendment to Third Amended and Restated Terminal Services Agreement, dated March 1, 2017, between MPLX Terminals LLC and Marathon Petroleum Company LP

Exhibit 10.102 Fourth Amendment to the Third Amended and Restated Terminal Services Agreement This Fourth Amendment to the Third Amended and Restated Terminal Services Agreement (“Amendment”) is dated July 1, 2019 by and between Marathon Petroleum Company LP (“MPC”), a Delaware limited partnership whose offices are located at 539 South Main Street, Findlay, Ohio 45840 and MPLX Terminals LLC (“Term

Power of Attorney of Directors and Officers of MPLX GP LLC

Exhibit 24.1 POWER OF ATTORNEY KNOW ALL BY THESE PRESENTS, that each of the undersigned officers and directors of MPLX GP LLC, a Delaware limited liability company and general partner of MPLX LP, a Delaware limited partnership (the “Registrant”), does hereby constitute and appoint Michael J. Hennigan, Pamela K.M. Beall and C. Kristopher Hagedorn, and each of them, as his or her true and lawful att

MPLX LP Reports Fourth-Quarter and Full-Year Financial Results

EX-99.1 2 mplxq42019earningsrele.htm EXHIBIT 99.1 MPLX LP Reports Fourth-Quarter and Full-Year Financial Results • Reported fourth-quarter net loss attributable to MPLX of $581 million and full-year net income attributable to MPLX of $1.0 billion; includes non-cash impairment charges of $1.2 billion in fourth quarter primarily related to goodwill associated with the Andeavor Logistics G&P business