Stock

MBX

MBX Biosciences, Inc.

Latest close $315 of 27 marquee funds currently hold1 CUSIP mapped

Current holders

27 funds tracked

Ever held

Current + past

New this quarter

Exited this quarter

Marquee-fund ownership over time

Nov 14, 2024Aug 14, 2025Feb 17, 2026May 15, 2026

Now

This quarter's activity

New positions opened

None.

Positions exited

Current holders

Sorted by tenure (longest first)

Fund	First disclosed	Held	Entry price	Latest close	Return on entry
Citadel Advisors re-entered	Q4 2024(8Q snapshot)	6Q	$19	$31	+59%
Millennium Management	Q4 2024(8Q snapshot)	6Q	$19	$31	+59%
Two Sigma Investments re-entered	Q2 2025(8Q snapshot)	4Q	$11	$31	+191%
AQR Capital Management	Q3 2025(8Q snapshot)	3Q	$13	$31	+135%
D.E. Shaw	Q1 2026(8Q snapshot)	1Q	$39	$31	-21%

“Return on entry” is the price-only move from the fund's first disclosure to today — it ignores any adds, trims, or dividends. A fund that built its position over multiple quarters has a true cost basis somewhere between entry price and latest close; this figure is the upper bound.

Past holders

Funds that exited at some point

Fund	Last entry	Exited	Entry → Exit	Return
Point72 Asset Management 2× in & out	Q2 2025	Q2 2026	→ $32	+205%
Renaissance Technologies	Q1 2026	Q2 2026	→ $35	-7%
Soros Fund Management	Q4 2024	Q1 2025	→ $10	-47%

Insider activity

Form 4 — officers, directors, 10%+ owners

Filed within two business days of each transaction by anyone with material insider status at MBX Biosciences, Inc.. Pair with the holders table above as a sanity check: heavy insider buying alongside marquee-fund accumulation is the strongest accumulation signal; heavy insider selling alongside fund exits is the strongest distribution signal.

Filings · last 30d

Filings · last 90d

Total on file

Recent SEC buffer

Most recent

Jun 5, 2026

30d / 90d windows measured from Jun 5, 2026 — the most recent Form 4 on file — not from today.

Showing 15 of 67 recent Form 4 filings. Browse all on EDGAR ↗

Fundamentals

XBRL · MBX Biosciences, Inc.

Annual figures sourced directly from MBX Biosciences, Inc.'s 10-K / 10-Q filings via SEC EDGAR XBRL. Latest fiscal year and the year-over-year change, with up to ten years of history.

Net income

-$86.97M

FY2025-40% YoY

EPS (diluted)

$-2.38

FY2025+59% YoY

Free cash flow(?)

-$81.88M

FY2025-47% YoY

Recent SEC filings

10-K · 10-Q · 8-K · 13D/G · proxy

The most recent material filings for MBX Biosciences, Inc. — earnings, material events, ownership disclosures, proxy statements. Form 4 insider activity is shown in the panel above.

Trade history

Every open→close lifecycle across tracked funds

Fund	Open date	Close date	Open price	Close price / current	Return
D.E. Shaw	Q1 2026	open	$39	$31	-21%
Renaissance Technologies	Q1 2026	Q2 2026	$38	$35	-7%
Citadel Advisors	Q4 2025	open	$25	$31	+25%
Two Sigma Investments	Q4 2025	open	$25	$31	+25%
AQR Capital Management	Q3 2025	open	$13	$31	+135%
Two Sigma Investments	Q2 2025	Q3 2025	$11	$13	+24%
Point72 Asset Management	Q2 2025	Q2 2026	$11	$32	+205%
Citadel Advisors	Q4 2024	Q2 2025	$19	$11	-45%
Soros Fund Management	Q4 2024	Q1 2025	$19	$10	-47%
Millennium Management	Q4 2024	open	$19	$31	+59%
Point72 Asset Management	Q4 2024	Q1 2025	$19	$10	-47%

Caveats

Covers only the 27 marquee funds tracked here, not the full institutional universe. A “0 holders” reading does not mean unowned.
Heavy funds (Renaissance Technologies, Citadel Advisors, Soros Fund Management, Two Sigma Investments, D.E. Shaw, AQR Capital Management, Millennium Management, Point72 Asset Management) use 8-quarter snapshots, so their pre-2024 history is missing.
“Current” reflects each fund's most recent 13F — filings lag the actual trade by up to 45 days; positions shown may have changed since.
Cost = price at the entry filing date. Re-entered positions show the most recent open lot.
Options, ADRs, and unmapped CUSIPs are excluded from the follower-backtest pipeline that produces these snapshots, so certain holding types won't appear here.