$MPLX

$58.30 +$0.19 (0.33%) After hours

$MPLX Overview Financial Statements SEC Filings Executives News Red Flags Capital Raising Ownership Insider Transactions Congressional Trades

Ownership

13F as of Q2 2026 · 1.01B shares outstanding

Who owns MPLX?

By type of holder

Institutions 100.0% Insiders 0.0% Everyone else 0.0%

Concentration Top 10 holders own 164.2%

BlackRock, Inc. 40.7% · Vanguard Capital Management LLC 26.6%

Institutional ownership

100.0%

0 pts vs last qtr

Institutional holders

4,580

+232 vs last qtr

Net shares bought

+80.1M

by institutions in Q2 2026

New / sold out

444 / 212

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

Norges Bank NEW +60.9M
Capital International Investors NEW +22.7M

Biggest sellers in Q2 2026

Wellington Management Group LLP −17.6M
Franklin Resources Inc −13.2M

Who is planning to sell?

No insider has filed a notice of proposed sale (Form 144) for MPLX LP in the last 12 months.

Is your stake being diluted?

There are not yet two fiscal years of reported share counts for MPLX LP.

How patient are the owners?

Institutional shares by how long they've been held

5+ years87% 3–5 years2% 1–3 years5% Under 1 year6%

Quarterly turnover

6.0%

of institutional shares changed hands

Top 10 managers, median time held

5 years

Super Investors

Investment managers reporting MPLX on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
B BlackRock, Inc.	412.5M	40.68%	−7.0M (−1.7%)	≤2021	0.7%
Shares held by quarter Peak holding435.0M (Q4'25) Change over 8 quarters−3.9M Share of the company40.680% BlackRock, Inc.'s full portfolio →
VC Vanguard Capital Management LLC	269.7M	26.60%	+567.0K (+0.2%)	≤2021	0.7%
Shares held by quarter Peak holding269.7M (Q2'26) Change over 8 quarters+269.7M Share of the company26.600% Vanguard Capital Management LLC's full portfolio →

BlackRock, Inc.

412.5M

% of company

40.68%

Change vs last qtr

−7.0M (−1.7%)

Held since

≤2021

Vanguard Capital Management LLC

269.7M

% of company

26.60%

Change vs last qtr

+567.0K (+0.2%)

Held since

≤2021

28 more super investors behind a free account

See every manager holding MPLX LP, how their position has changed, and how long they've held it.

Institutional Funds

Mutual funds and ETFs reporting MPLX on Form N-PORT; together they hold 150.7% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
VT Vanguard Total Stock Market Index Fund Vanguard Index Funds	$14.8B	126.4M	12.47%	0.65%	June 30, 2026
V5 Vanguard 500 Index Fund Vanguard Index Funds	$13.1B	109.5M	10.80%	0.78%	June 30, 2026

Vanguard Total Stock Market Index Fund

Vanguard Index Funds

Position value

$14.8B

% of company

12.47%

% of the fund

0.65%

As of

June 30, 2026

Vanguard 500 Index Fund

Vanguard Index Funds

Position value

$13.1B

% of company

10.80%

% of the fund

0.78%

As of

June 30, 2026

23 more funds behind a free account

See every fund holding MPLX LP and how much of the fund the position is.

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