MPLX

mplx-20260804

0001552000false00015520002026-08-042026-08-04

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, 2026

MPLX LP

(Exact name of registrant as specified in its charter)

Delaware001-3571427-0005456

(State or other jurisdiction of incorporation)(Commission File Number)(IRS Employer Identification No.)

200 E. Hardin Street, Findlay, Ohio 45840

(Address of principal executive offices) (Zip code)

Registrant’s telephone number, including area code: (419) 422-2121

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each classTrading symbol(s)Name of each exchange on which registered

Common Units Representing Limited Partnership InterestsMPLXNew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

☐

Item 2.02Results of Operations and Financial Condition

On August 4, 2026, MPLX LP issued a press release announcing its financial results for the quarter ended June 30, 2026. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Information in this Item 2.02 and Exhibit 99.1 of Item 9.01 below shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise incorporated by reference into any filing pursuant to the Securities Act of 1933, as amended, or the Exchange Act except as otherwise expressly stated in such a filing.

Item 9.01Financial Statements and Exhibits

(d) Exhibits.

Exhibit Number Description

99.1 Press Release issued by MPLX LP on August 4, 2026

104Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

MPLX LP

By:MPLX GP LLC, its General Partner

Date: August 4, 2026By:/s/ C. Kristopher Hagedorn

Name: C. Kristopher Hagedorn

Title: Executive Vice President and Chief Financial Officer

mplx-20260505

0001552000false00015520002026-05-052026-05-05

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, 2026

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 Employer Identification No.)

200 E. Hardin Street, Findlay, Ohio 45840

(Address of principal executive offices) (Zip code)

Registrant’s telephone number, including area code: (419) 422-2121

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each classTrading symbol(s)Name of each exchange on which registered

Common Units Representing Limited Partnership InterestsMPLXNew York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

☐

Item 2.02Results of Operations and Financial Condition

On May 5, 2026, MPLX LP issued a press release announcing its financial results for the quarter ended March 31, 2026. The press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Information in this Item 2.02 and Exhibit 99.1 of Item 9.01 below shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise incorporated by reference into any filing pursuant to the Securities Act of 1933, as amended, or the Exchange Act except as otherwise expressly stated in such a filing.

Item 9.01Financial Statements and Exhibits

(d) Exhibits.

Exhibit Number Description

99.1 Press Release issued by MPLX LP on May 5, 2026

104Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

MPLX LP

By:MPLX GP LLC, its General Partner

Date: May 5, 2026By:/s/ C. Kristopher Hagedorn

Name: C. Kristopher Hagedorn

Title: Executive Vice President and Chief Financial Officer

mplx-20260407

0001552000false00015520002026-04-072026-04-07

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 7, 2026

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 Employer

Identification No.)

200 E. Hardin Street, Findlay, Ohio 45840

(Address of principal executive offices) (Zip code)

Registrant’s telephone number, including area code:  (419) 422-2121

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant

under any of the following provisions:

☐

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading

symbol(s)

Name of each exchange on which registered

Common Units Representing Limited Partnership

Interests

MPLX

New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of

1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period

for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

☐

Item 1.01

Entry into a Material Definitive Agreement.

On April 7, 2026, MPLX LP, a Delaware master limited partnership (“MPLX”), entered into a $2.5 billion, five-year Revolving

Credit Agreement with 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., Goldman Sachs Banks USA, Mizuho

Bank, Ltd., MUFG Bank, Ltd., RBC Capital Markets,  Sumitomo Mitsui Banking Corporation 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., Goldman Sachs Bank USA, Mizuho Bank, Ltd., MUFG Bank, Ltd., Royal Bank of Canada,

Sumitomo Mitsui Banking Corporation and The Toronto-Dominion Bank, New York Branch, as documentation agents, and the

other lenders and issuing banks that are parties thereto (the “New MPLX Credit Agreement”).

The New MPLX Credit Agreement replaces the previously effective 2022 Credit Agreement (as defined below) and is intended to

be used for general partnership purposes. There were no borrowings outstanding under the 2022 Credit Agreement at the time of

its termination, and as of the date hereof, there are no borrowings outstanding under the New MPLX Credit Agreement. As of

March 31, 2026, MPLX had $1.5 billion of cash and cash equivalents.

The New MPLX Credit Agreement provides for a $2.5 billion unsecured revolving credit facility that matures on April 7, 2031.

MPLX has an option to increase the aggregate commitments by up to an additional $1.0 billion, subject to, among other

conditions, the consent of the lenders whose commitments would be increased. In addition, MPLX may request up to two one-

year extensions of the maturity date of the New MPLX Credit Agreement subject to, among other conditions, the consent of

lenders holding a majority of the commitments, provided that the commitments of any non-consenting lenders will terminate on

the then-effective maturity date. The New MPLX Credit Agreement includes sub-facilities for swing-line loans of up to $150.0

million and letters of credit of up to $150.0 million (which may be increased to up to $200.0 million upon receipt of additional letter

of credit issuing commitments).

Commitment fees ranging from 10.0 basis points to 25.0 basis points per annum, depending on MPLX’s credit ratings, accrue on

the unused commitments under the New MPLX Credit Agreement. Borrowings under the New MPLX Credit Agreement bear

interest, at MPLX’s election, at either (i) the Adjusted Term SOFR (as defined in the New MPLX Credit Agreement) plus a margin

ranging from 100.0 basis points to 175.0 bas