MPLX (MPLX) FWP Free writing prospectus

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 expenses) to the Issuer:	$987,830,000
Trade Date:	August 8, 2022
Settlement Date**:	August 11, 2022 (T+3)
Principal Amount:	$1,000,000,000
Maturity Date:	September 1, 2032
Coupon:	4.950%
Price to Public:	99.433% of the principal amount plus accrued interest, if any, from August 11, 2022
Yield to Maturity:	5.022%
Spread to Benchmark Treasury:	+225 bps
Benchmark Treasury:	2.875% due May 15, 2032
Benchmark Treasury Price / Yield:	100-28 / 2.772%
Interest Payment Dates:	March 1 and September 1, commencing March 1, 2023, to holders of record at the close of business on the preceding February 15 and August 15, respectively

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Optional Redemption Provisions:

Make-Whole Call:	T+35 bps (at any time before June 1, 2032)
Par Call:	At any time on or after June 1, 2032
CUSIP / ISIN:	55336V BU3 / US55336VBU35
Joint Book-Running Managers:	Barclays Capital Inc. Mizuho Securities USA LLC Wells Fargo Securities, LLC
	BofA Securities, Inc. Citigroup Global Markets Inc. J.P. Morgan Securities LLC MUFG Securities Americas Inc. RBC Capital Markets, LLC TD Securities (USA) LLC
Co-Managers:	Truist Securities, Inc. Scotia Capital (USA) Inc. SMBC Nikko Securities America, Inc. U.S. Bancorp Investments, Inc. BNP Paribas Securities Corp. PNC Capital Markets LLC Fifth Third Securities, Inc. Huntington Securities, Inc. Morgan Stanley & Co. LLC Comerica Securities, Inc. Siebert Williams Shank & Co., LLC Loop Capital Markets LLC BNY Mellon Capital Markets, LLC

* A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision or withdrawal at any time.

The issuer has filed a registration statement (including a prospectus) and a prospectus supplement with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement, the prospectus supplement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling Barclays Capital Inc., telephone: (toll-free) 1-888-603-5847; Mizuho Securities USA LLC, telephone: (toll-free) 1-866-271-7403; or Wells Fargo Securities, LLC, telephone: (toll-free) 1-800-645-3751.

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Any legends, disclaimers or other notices that may appear below are not applicable to this communication and should be disregarded. Such legends, disclaimers or other notices have been automatically generated as a result of this communication having been sent via Bloomberg or another system.

** It is expected that delivery of the notes will be made against payment therefor on or about August 11, 2022, which is the third business day following the date hereof (such settlement cycle being referred to as “T+3”). Under Rule 15c6-1 under the Exchange Act, trades in the secondary market generally are required to settle in two business days unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade the notes prior to the date that is two business days prior to the settlement date will be required, by virtue of the fact that the notes initially will settle in T+3, to specify an alternative settlement cycle at the time of any such trade to prevent a failed settlement. Purchasers of the notes who wish to trade the notes prior to their date of delivery hereunder should consult their own advisors.

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