Who owns MBX Biosciences, Inc. Common Stock?
Institutional ownership of MBX from SEC Form 13F filings across 118 reporting managers. All positions are from one synchronized reporting period — 2026-06-30 books, filed up to 45 days after quarter end — so every row is comparable.
118
13F holders
$1.25B
value, 2026 filers
49.6%
of shares outstanding (23.6M sh)
29
new positions (2026 filers)
Top institutional holders
ordered by shares owned · positions as of 2026-06-30· % of fund = share of the manager's own book · % of co. = share of MBX's shares outstanding
| # | Manager | Shares | Value | % of fund | % of co. | Δ shares QoQ |
|---|---|---|---|---|---|---|
| 1 | FMR LLC | 5.3M | $293.8M | 0.0% | 11.2% | +81.3% |
| 2 | WELLINGTON MANAGEMENT GROUP LLP | 5.0M | $274.8M | 0.0% | 10.5% | +55.9% |
| 3 | BlackRock, Inc. | 3.3M | $183.5M | 0.0% | 7% | +13.0% |
| 4 | VANGUARD CAPITAL MANAGEMENT LLC | 1.5M | $81.6M | 0.0% | 3.1% | -50.0% |
| 5 | Woodline Partners LP | 900,092 | $49.7M | 0.2% | 1.9% | -50.0% |
| 6 | PRICE T ROWE ASSOCIATES INC /MD/ | 814,807 | $44,978 | 0.0% | 1.7% | -20.8% |
| 7 | GEODE CAPITAL MANAGEMENT, LLC | 773,072 | $42.7M | 0.0% | 1.6% | +15.3% |
| 8 | GOLDMAN SACHS GROUP INC | 459,005 | $25.3M | 0.0% | 1% | +0.2% |
| 9 | MARSHALL WACE, LLP | 401,885 | $22.2M | 0.0% | 0.8% | +540.9% |
| 10 | VANGUARD PORTFOLIO MANAGEMENT LLC | 346,717 | $19.1M | 0.0% | 0.7% | +18.2% |
| 11 | BANK OF AMERICA CORP /DE/ | 298,927 | $16.5M | 0.0% | 0.6% | +939.7% |
| 12 | Candriam S.C.A. | 289,893 | $16.0M | 0.1% | 0.6% | -1.5% |
| 13 | UBS Group AG | 272,747 | $15.1M | 0.0% | 0.6% | -21.4% |
| 14 | FRANKLIN RESOURCES INCNEW | 252,665 | $13.9M | 0.0% | 0.5% | new |
| 15 | Schonfeld Strategic Advisors LLC | 248,670 | $13.7M | 0.0% | 0.5% | +100.8% |
| 16 | MORGAN STANLEY | 248,558 | $13.7M | 0.0% | 0.5% | +687.5% |
| 17 | NORTHERN TRUST CORP | 246,678 | $13.6M | 0.0% | 0.5% | +17.1% |
| 18 | Sixth Street Partners Management Company, L.P.NEW | 233,095 | $12.9M | 2.2% | 0.5% | new |
| 19 | CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 233,095 | $12.9M | 0.0% | 0.5% | +8.5% |
| 20 | MILLENNIUM MANAGEMENT LLC | 226,151 | $12.5M | 0.0% | 0.5% | -59.9% |
| 21 | VANGUARD FIDUCIARY TRUST CO | 201,429 | $11.1M | 0.0% | 0.4% | +18.4% |
| 22 | D. E. Shaw & Co., Inc. | 182,767 | $10.1M | 0.0% | 0.4% | -36.7% |
| 23 | JPMORGAN CHASE & CO | 139,611 | $7.5M | 0.0% | 0.3% | -5.1% |
| 24 | TWO SIGMA INVESTMENTS, LP | 113,475 | $6.3M | 0.0% | 0.2% | -1.4% |
| 25 | Burkehill Global Management, LP | 100,000 | $5.5M | 0.2% | 0.2% | 0.0% |
Source: SEC Form 13F-HR filings (institutional managers over $100M in US-listed positions). 13Fs disclose long positions only, up to 45 days after quarter end; each manager's latest filed quarter is shown per row and dollar values are the manager's filed marks. Aggregates labeled "2026 filers" count only managers whose latest book is a 2026 quarter. Related: valuation · options positioning · supply chain. Research, not investment advice.