$MIRM

$85.56 +$2.29 (2.75%) Close

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

Ownership

13F as of Q2 2026 · 64.9M shares outstanding

Who owns MIRM?

By type of holder

Institutions 100.0% Insiders 0.0% Everyone else 0.0%

Concentration Top 10 holders own 111.8%

Rubric Capital Management LP 23.6% · 683 Capital Management, LLC 18.1%

Institutional ownership

100.0%

0 pts vs last qtr

Institutional holders

357

+11 vs last qtr

Net shares bought

−15.8M

by institutions in Q2 2026

New / sold out

64 / 53

positions opened vs closed

How is ownership changing?

Institutions, last 8 quarters

Biggest buyers in Q2 2026

Jupiter Topco LLC NEW +5.9M
FMR LLC +1.7M

Biggest sellers in Q2 2026

EcoR1 Capital, LLC −12.4M
Janus Henderson Group PLC SOLD OUT −6.9M

Who is planning to sell?

Notices of proposed sale, last 12 months

$40.4M

36 notices from 9 people

Shares covered

446.1K

0.69% of the company

Arranged in advance

86%

of the value is under a 10b5-1 plan

Under a 10b5-1 plan No plan

Largest proposed sellers

Michael Grey Director 10b5-1 $11.1M
Christopher Peetz Officer 10b5-1 $10.3M

Every notice on Red Flags →

A Form 144 is notice of a planned sale, not the sale itself. What insiders actually sold is on Insider Transactions.

Is your stake being diluted?

Diluted share count, FY2021–FY2025

+65.6%

+13.43% a year

Each share's claim on the business

−39.6%

shrank without buying or selling a share

Spent on buybacks vs paid in stock

— vs $205M

over 5 fiscal years

Diluted shares, split-adjusted

Buybacks Stock-based comp

How patient are the owners?

Institutional shares by how long they've been held

5+ years42% 3–5 years27% 1–3 years8% Under 1 year23%

Quarterly turnover

19.5%

of institutional shares changed hands

Top 10 managers, median time held

4.3 years

Super Investors

Investment managers reporting MIRM on Form 13F

Holder	Shares	% of company	Change vs last qtr	Held since	% of their book
RC Rubric Capital Management LP	15.3M	23.57%	Unchanged	≤2021	0.0%
Shares held by quarter Peak holding15.3M (Q3'24) Change over 8 quarters0 Share of the company23.570% Rubric Capital Management LP's full portfolio →
6C 683 Capital Management, LLC	11.8M	18.14%	−222.1K (−1.9%)	2022	0.2%
Shares held by quarter Peak holding15.0M (Q4'25) Change over 8 quarters+6.9M Share of the company18.140% 683 Capital Management, LLC's full portfolio →

Rubric Capital Management LP

15.3M

% of company

23.57%

Change vs last qtr

Unchanged

Held since

≤2021

683 Capital Management, LLC

11.8M

% of company

18.14%

Change vs last qtr

−222.1K (−1.9%)

Held since

2022

28 more super investors behind a free account

See every manager holding Mirum Pharmaceuticals, Inc., how their position has changed, and how long they've held it.

Institutional Funds

Mutual funds and ETFs reporting MIRM on Form N-PORT; together they hold 43.2% of the company

Fund	Position value	Shares	% of company	% of the fund	As of
VT Vanguard Total Stock Market Index Fund Vanguard Index Funds	$193M	1.6M	2.54%	0.01%	June 30, 2026
IR iShares Russell 2000 ETF iShares Trust	$143M	1.2M	1.88%	0.17%	June 30, 2026

Vanguard Total Stock Market Index Fund

Vanguard Index Funds

Position value

$193M

% of company

2.54%

% of the fund

0.01%

As of

June 30, 2026

iShares Russell 2000 ETF

iShares Trust

Position value

$143M

% of company

1.88%

% of the fund

0.17%

As of

June 30, 2026

23 more funds behind a free account

See every fund holding Mirum Pharmaceuticals, Inc. and how much of the fund the position is.

Insiders and 5%+ holders

From Forms 3/4/5 and Schedules 13D/G

Holder	Shares	% of company	Change vs last qtr	8 quarters	Held since	% of their book
PJ Patrick J. Heron 5%+ holder 13D · 6.8%	4.1M	6.33%	—	—	—	—
This holder reports through Schedule 13D/G, not a quarterly 13F. Share of the company6.330% Disclosed stake13D · 6.8% View the 13D/G filing →
JN James N. Topper 5%+ holder 13D · 6.7%	4.0M	6.20%	—	—	—	—
This holder reports through Schedule 13D/G, not a quarterly 13F. Share of the company6.200% Disclosed stake13D · 6.7% View the 13D/G filing →

Patrick J. Heron

5%+ holder13D · 6.8%

4.1M

% of company

6.33%

Change vs last qtr

—

Held since

—

James N. Topper

5%+ holder13D · 6.7%

4.0M

% of company

6.20%

Change vs last qtr

—

Held since

—

27 more holders behind a free account

See every insider and 5%+ holder of Mirum Pharmaceuticals, Inc..

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