Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in MBX held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | Frazier Life Sciences Management, L.P. | 6.7M | $198.6M | 0.0% | 19.802% | 5.11% |
| 2 | ORBIMED ADVISORS LLC | 3.6M | $108.6M | -7.6% | 10.829% | 2.29% |
| 3 | NEA Management Company, LLC | 3.6M | $107.9M | 0.0% | 10.760% | 6.13% |
| 4 | WELLINGTON MANAGEMENT GROUP LLP | 3.2M | $95.3M | -4.7% | 9.501% | 0.02% |
| 5 | BlackRock, Inc. | 2.9M | $87.8M | +0.7% | 8.756% | 0.00% |
| 6 | FMR LLC | 2.9M | $87.7M | +18550.3% | 8.742% | 0.00% |
| 7 | Deep Track Capital, LP | 2.8M | $82.3M | -15.2% | 8.209% | 1.70% |
| 8 | NVP Associates, LLC | 2.1M | $63.8M | 0.0% | 6.359% | 36.20% |
| 9 | Polar Capital Holdings Plc | 1.6M | $48.4M | — | 4.829% | 0.17% |
| 10 | BRAIDWELL LP | 1.5M | $44.6M | +46.5% | 4.443% | 1.49% |
| 11 | VANGUARD CAPITAL MANAGEMENT LLC | 1.5M | $44.1M | — | 4.399% | 0.00% |
| 12 | Aaron Wealth Advisors LLC | 1.2M | $34.9M | +1568.8% | 3.477% | 1.98% |
| 13 | Cormorant Asset Management, LP | 1.1M | $33.4M | 0.0% | 3.334% | 1.68% |
| 14 | DRIEHAUS CAPITAL MANAGEMENT LLC | 1.0M | $30.4M | -27.7% | 3.031% | 0.22% |
| 15 | CITADEL ADVISORS LLC | 968K | $28.9M | +15.9% | 2.882% | 0.01% |
| 16 | Kynam Capital Management, LP | 935K | $27.9M | 0.0% | 2.783% | 1.74% |
| 17 | Woodline Partners LP | 900K | $26.9M | -10.0% | 2.679% | 0.10% |
| 18 | EVENTIDE ASSET MANAGEMENT, LLC | 890K | $26.6M | 0.0% | 2.649% | 0.44% |
| 19 | Caligan Partners LP | 849K | $25.3M | — | 2.526% | 1.76% |
| 20 | Parkman Healthcare Partners LLC | 800K | $23.9M | -9.7% | 2.381% | 2.48% |
| 21 | STATE STREET CORP | 787K | $23.5M | +17.0% | 2.343% | 0.00% |
| 22 | EcoR1 Capital, LLC | 777K | $23.2M | -63.4% | 2.313% | 0.98% |
| 23 | GEODE CAPITAL MANAGEMENT, LLC | 670K | $20.0M | +3.2% | 1.996% | 0.00% |
| 24 | TCG Crossover Management, LLC | 650K | $19.4M | 0.0% | 1.935% | 0.56% |
| 25 | MILLENNIUM MANAGEMENT LLC | 564K | $16.8M | +22.1% | 1.680% | 0.01% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in MBX — a direct measure of their conviction.
Filings activity in MBX during Q1 2026, grouped by how each filer changed its position.
7 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 153 | +12% | 128.69% | +2.24 pp | $1.54B | +1.8% |
| Q4 2025 | 137 | +20% | 126.45% | +56.75 pp | $1.51B | +81% |
| Q3 2025 | 114 | +30% | 69.70% | +35.69 pp | $831M | +105% |
| Q2 2025 | 88 | +10% | 34.01% | +12.64 pp | $406M | +59% |
| Q1 2025 | 80 | +27% | 21.37% | 27.61 pp | $255M | 56% |
| Q4 2024 | 63 | +40% | 48.98% | 13.96 pp | $584M | 22% |
| Q3 2024 | 45 | — | 62.94% | — | $751M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying MBX stock.
Based on Q1 2026 13F filings, institutional ownership of MBX Biosciences, Inc. Common Stock stands at 128.7%, held across 153 reporting institutions.
Frazier Life Sciences Management, L.P. is the largest reported institutional holder of MBX, with approximately 6,652,013 shares worth $0.20B as of Q1 2026.
Yes — 2 widely-followed marquee investors appear among the top 25 institutional holders of MBX, including CITADEL ADVISORS LLC, MILLENNIUM MANAGEMENT LLC.
Our composite Smart Money Score for MBX is 69 out of 100 (Bullish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
38 institutions opened new positions in MBX during Q1 2026, while 22 fully exited. 36 added to existing positions and 79 trimmed.
MBX institutional ownership rose by 2.24 percentage points quarter-over-quarter, with a net change of +16 holders.
The top 10 institutions account for 60.2% of all reported 13F value in MBX, and the top 25 account for 86.6%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
MBX Biosciences, Inc. Common Stock (MBX) Institutional Ownership