What SEC filings does MPLX LP submit to the SEC?

MPLX LP (MPLX) submits several types of SEC filings including Form 4 (insider transactions), Form 144 (proposed insider sales), 8-K reports (material events such as earnings releases, acquisitions, leadership changes), and periodic reports — the 10-Q (quarterly) and 10-K (annual). All filings are publicly available through SEC EDGAR.

What does a Form 4 filing tell me about MPLX?

A Form 4 for MPLX discloses a transaction by a company insider — typically a director, officer, or 10%+ shareholder. It shows the source-reported date, number of shares, price, and updated ownership. These facts do not establish motive or predict future returns.

How do I interpret an 8-K filing from MPLX LP?

An 8-K signals a material event requiring prompt disclosure. Common triggers include earnings pre-announcements, acquisitions, leadership appointments or departures, credit changes, or regulatory actions. Read the item codes inside the filing to understand exactly what was disclosed before drawing conclusions.

What is the difference between a 10-K and 10-Q for MPLX?

The 10-K is MPLX LP's annual report with fully audited financial statements, comprehensive MD&A, and complete risk factor disclosures — filed 60–90 days after fiscal year-end. The 10-Q is a lighter quarterly report with unaudited financials filed for the first three quarters. Together they provide a continuous financial picture of the company.

Where can I see all MPLX SEC filings directly on EDGAR?

You can view all historical MPLX LP filings on the SEC EDGAR company page for MPLX. Each filing card on this page links directly to the original SEC document.

How often does MPLX LP file with the SEC?

MPLX LP files one 10-K per year and up to three 10-Qs per year. Form 4 insider transactions must be reported within two business days of each trade, so the frequency depends on how often insiders are buying or selling MPLX shares. 8-K filings occur whenever a material event happens — which can be several times per quarter for an active company.

MPLX SEC Filing News — MPLX LP

Latest SEC filings for MPLX LP (MPLX) explained in plain English. Covers insider buying and selling (Form 4), proposed insider sales (Form 144), material company events (8-K), and quarterly & annual reports (10-Q / 10-K). StrongBuyAnalytics provides navigation and brief excerpts or summaries; original filings remain at the SEC/source links and were authored by their filers, not StrongBuyAnalytics. Filing dates shown are source dates. Coverage and detection can be delayed or incomplete because of SEC availability, amendments, parsing, caching, or outages. Latest source filing date shown: 2026-08-24.

MPLX LP owns and operates midstream energy infrastructure and logistics assets primarily in the United States. It operates in two segments, Crude Oil and Products Logistics; and Natural Gas and NGL Services. The company is involved in the gathering, processing, and transportation of natural gas; gathering, transportation, fractionation, storage, and marketing of natural gas liquids; gathering, storage, transportation, and distribution of crude oil and refined products, as well as other hydrocarb…

Sector: Energy Industry: Oil & Gas Midstream Market Cap: $59.0B CIK: 1552000

Total Filings

Bullish Classifications

Bearish Classifications

Insider Transactions

Material Events (8-K)

Periodic Reports

What you're looking at: Each item below is parsed from an actual SEC filing submitted by MPLX LP. Form 4 = confirmed insider transaction · Form 144 = proposed sale notice · 8-K = material event (earnings, M&A, leadership change, etc.) · 10-Q / 10-K = quarterly / annual report.

MPLX Filing Activity Snapshot 2026-05-04 — 2026-08-24

Insider Transactions (Form 4)

0 buys vs 0 sells

Insider buying and selling activity is balanced in this period.

Insider Transactions 15 · Forms 3, 4 and 5

A Form 4 is filed within two business days of a company insider — an officer, a director, or a holder of more than ten percent of the stock — changing their position in the shares. All 15 filings in this group are Form 4s for MPLX LP.

The difficulty with reading these filings as a group is that a single form type covers transactions that mean entirely different things. An executive spending their own money to buy stock and an executive having shares withheld to pay tax on a vesting grant both appear as a Form 4. Every filing below is therefore tagged with the nature of the underlying transaction, taken from the transaction code reported on the form itself.

Across the 15 insider filings shown, the breakdown is 15 compensation award. None of the classified filings involved a discretionary open-market trade, so this period says nothing about what insiders think of the price.

What each transaction type means

Compensation award ×15: Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Form 4 Compensation award Tax / Compensation Filing 2026-08-18

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

Peiffer Garry L. (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,232	—	—

Filing: Form 4 (Insider Transaction) Insider: Peiffer Garry L. (Director) Shares: 1,232

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-08-18

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

Walker Ray N JR (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	81	—	—

Filing: Form 4 (Insider Transaction) Insider: Walker Ray N JR (Director) Shares: 81

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-08-18

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

SURMA JOHN P (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,563	—	—

Filing: Form 4 (Insider Transaction) Insider: SURMA JOHN P (Director) Shares: 1,563

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-08-18

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

STICE J MICHAEL (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	982	—	—

Filing: Form 4 (Insider Transaction) Insider: STICE J MICHAEL (Director) Shares: 982

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-08-18

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

SEMPLE FRANK M (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,072	—	—

Filing: Form 4 (Insider Transaction) Insider: SEMPLE FRANK M (Director) Shares: 1,072

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-08-18

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

HELMS CHRISTOPHER A (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,336	—	—

Filing: Form 4 (Insider Transaction) Insider: HELMS CHRISTOPHER A (Director) Shares: 1,336

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-08-18

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

Breves Christine S (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	218	—	—

Filing: Form 4 (Insider Transaction) Insider: Breves Christine S (Director) Shares: 218

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-05-19

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

Walker Ray N JR (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	78	—	—

Filing: Form 4 (Insider Transaction) Insider: Walker Ray N JR (Director) Shares: 78

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-05-19

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

SURMA JOHN P (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,656	—	—

Filing: Form 4 (Insider Transaction) Insider: SURMA JOHN P (Director) Shares: 1,656

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-05-19

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

STICE J MICHAEL (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,098	—	—

Filing: Form 4 (Insider Transaction) Insider: STICE J MICHAEL (Director) Shares: 1,098

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-05-19

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

SEMPLE FRANK M (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,194	—	—

Filing: Form 4 (Insider Transaction) Insider: SEMPLE FRANK M (Director) Shares: 1,194

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-05-19

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

Peiffer Garry L. (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,303	—	—

Filing: Form 4 (Insider Transaction) Insider: Peiffer Garry L. (Director) Shares: 1,303

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-05-19

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

HELMS CHRISTOPHER A (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	1,415	—	—

Filing: Form 4 (Insider Transaction) Insider: HELMS CHRISTOPHER A (Director) Shares: 1,415

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-05-19

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

Breves Christine S (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	276	—	—

Filing: Form 4 (Insider Transaction) Insider: Breves Christine S (Director) Shares: 276

View on SEC EDGAR → Open Filing Document →

Form 4 Compensation award Tax / Compensation Filing 2026-05-04

MPLX insider Form 4 filed for equity award, exercise, or tax withholding

Walker Ray N JR (Director) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

Shares were granted as compensation rather than purchased. No cash changed hands, so the filing reflects a pay decision by the company, not a judgement about the price.

Transactions reported on this filing
Code	Nature	Shares	Price	Value
`A`	Compensation award	2,246	—	—

Filing: Form 4 (Insider Transaction) Insider: Walker Ray N JR (Director) Shares: 2,246

View on SEC EDGAR → Open Filing Document →

Material Events 3 · Form 8-K

An 8-K reports a material event in the window between scheduled reports. There are 3 in this period for MPLX LP. Each 8-K names the item number it is filed under, and that number is the fastest way to tell a routine disclosure from a consequential one.

Item 2.02 is an earnings release, Item 5.02 is a change of directors or officers, and Item 1.01 or 2.01 covers a material agreement or a completed acquisition. Item 7.01 and Item 8.01 are the general-purpose disclosure items and carry no fixed meaning on their own.

Form 8-K Material Company Update 2026-08-24

MPLX filed 8-K — material company event

MPLX LP filed an 8-K with the SEC reporting a material event. Summary unavailable — view the original SEC filing for the full text.

Filing: 8-K (Material Event)

View on SEC EDGAR → Open Filing Document →

Form 8-K Material Company Update 2026-08-04

MPLX filed 8-K — material company event

MPLX LP filed an 8-K with the SEC reporting a material event. Summary unavailable — view the original SEC filing for the full text.

Filing: 8-K (Material Event)

View on SEC EDGAR → Open Filing Document →

Form 8-K Material Company Update 2026-05-05

MPLX filed 8-K — material company event

MPLX LP filed an 8-K with the SEC reporting a material event. Summary unavailable — view the original SEC filing for the full text.

Filing: 8-K (Material Event)

View on SEC EDGAR → Open Filing Document →

Periodic Reports 2 · Forms 10-K and 10-Q

The periodic reports are where the audited and reviewed financial statements live. This period contains 2 quarterly reports (10-Q) for MPLX LP.

The two are not equivalent in weight. A 10-K is audited by an external firm and includes the full risk factor disclosure, business description and management discussion; a 10-Q is unaudited, reviewed rather than examined, and much shorter. When a figure in a quarterly report is later revised, the annual report is usually where the correction appears.

An amended report — 10-K/A or 10-Q/A — restates or corrects something in the original filing, and is worth reading against the version it replaces.

Form 10-Q Quarterly Report 2026-08-04

MPLX filed Quarterly Report (10-Q)

MPLX LP filed its quarterly report with the SEC. This report includes unaudited financial statements and management discussion for the quarter.

Filing: 10-Q (Quarterly Report)

View on SEC EDGAR → Open Filing Document →

Form 10-Q Quarterly Report 2026-05-05

MPLX filed Quarterly Report (10-Q)

MPLX LP filed its quarterly report with the SEC. This report includes unaudited financial statements and management discussion for the quarter.

Filing: 10-Q (Quarterly Report)

View on SEC EDGAR → Open Filing Document →

How we classify MPLX LP's filings

Straight from EDGAR

Each displayed record links to an original source document. StrongBuyAnalytics provides navigation and brief excerpts or summaries, not the filing itself. Parsing may omit context or contain errors, so read the original document in full.

Transaction codes, not guesswork

The nature shown on each insider filing comes from the transaction code the filer entered on the form itself — P for an open-market purchase, A for a compensation award, F for shares withheld to pay tax, M for an option exercise. Where one filing contains several codes, the transaction table lists them line by line.

Why the distinction matters

Insider activity is routinely summarised as buying or selling, which flattens together decisions that mean very different things. Shares withheld for tax on a vesting grant are an automatic administrative step; shares bought on the open market are someone committing their own money at the current price.

What this page does not tell you

A filing records what happened, not why. Form 4 does not always disclose whether a sale was executed under a pre-arranged Rule 10b5-1 plan, and no single filing is a basis for a decision on MPLX. Read these alongside the fundamentals rather than in isolation.

Frequently Asked Questions — MPLX SEC Filings

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MPLX Full Analysis

Publisher, sources & limitations — September 15, 2026. StrongBuyAnalytics provides navigation and brief excerpts or summaries for educational use. Original filings remain at SEC EDGAR or other displayed source links; StrongBuyAnalytics does not author them. Filing dates are source dates, not publication dates for this page. Coverage can be delayed, incomplete, amended, or unavailable because of SEC/source availability, parsing, caching, or outages. Verify every material statement in the original filing.

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