MBX Institutional Ownership
Who owns MBX Biosciences, Inc. and what the big funds did with it last quarter, from every SEC 13F filing. 173 funds reported holding MBX at Jun 30, 2026, together owning 115.2% of the company.
- ▲98 buying vs 67 selling
- ▲Held by funds +5.1 pts
- ▲Funds holding +16
- ▼Superinvestors: 0 added, 2 cut
- ●Put/call not meaningful
What the filings show, not a forecast. Positions can be up to 45 days old and leave out short sales.
Funds holding and ownership
8 quartersQuarter over quarter
all 13F filers| Q2 2026 | This quarter | Q1 2026 | Change |
|---|---|---|---|
| Funds holding | 173 | 157 | +10.2% |
| In funds' top 10 | 8 | 6 | +33.3% |
| 13F shares | 55.5M | 53M | +4.6% |
| Held by funds | 115.2% | 110.1% | +5.1 pts |
| New positions | 36 | 33 | +9.1% |
| Increased | 62 | 43 | +44.2% |
| Reduced | 47 | 47 | 0.0% |
| Sold out | 20 | 18 | +11.1% |
| Calls (shares) | 200K | 0 | – |
| Puts (shares) | 200K | 0 | – |
| Put/call ratio | 1.00 | – | – |
Buyers vs sellers
adding or new vs cutting or sold outSuperinvestors in MBX
All superinvestors →
Who owns MBX
share of fund held shares- Index and passive funds14.1%
- Active managers and hedge funds82.3%
- Banks and brokers3.2%
- Pensions, insurers and other0.3%
The top 10 holders own 63.6% of all MBX shares that funds reported. Groups are our own grouping of filers by name.
Put/call ratio
funds' options, market makers left outAbove 1 means funds hold more puts than calls, a sign of hedging or bets on a fall. Options are valued at the underlying shares.
Filed so far for Q3 2026
34 funds changed their position- Sowell Financial Services LLCNew+53K sh
- Profund Advisors LLCAdded+16K sh
- Alps Advisors IncAdded+16K sh
- Aaron Wealth Advisors LLCAdded+7,972 sh
- Exchange Traded Concepts, LLCTrimmed−6,891 sh
🔒 Free account: see all 20.
Top holders
Q2 2026| # | Fund | Of company | Shares | Value | Change |
|---|---|---|---|---|---|
| 1 | Frazier Life Sciences Management, L.P. | 13.81% | 6.7M | $367M | 0 |
| 2 | Fmr LLC | 11.05% | 5.3M | $294M | +2.4M |
| 3 | Wellington Management Group LLP | 10.34% | 5M | $275M | +1.8M |
| 4 | NEA Management Company, LLC | 7.51% | 3.6M | $200M | 0 |
| 5 | Orbimed Advisors LLC | 7.12% | 3.4M | $189M | −209K |
| 6 | BlackRock, Inc. | 6.90% | 3.3M | $183M | +382K |
| 7 | Paradigm Biocapital Advisors LP | 5.21% | 2.5M | $138M | +2.5M |
| 8 | Nvp Associates, LLC | 4.44% | 2.1M | $118M | 0 |
| 9 | Deep Track Capital, LP | 3.60% | 1.7M | $95.6M | −1M |
| 10 | Polar Capital Holdings Plc | 3.34% | 1.6M | $88.8M | −14K |
- Paradigm Biocapital Advisors LP+2.5M sh+$138M
- Fmr LLC+2.4M sh+$132M
- Wellington Management Group LLP+1.8M sh+$98.6M
- BlackRock, Inc.+382K sh+$21.1M
- Marshall Wace, LLP+339K sh+$18.7M
- Soleus Capital Management, L.P.+336K sh+$18.6M
- Bank of America Corp /de/+270K sh+$14.9M
- Franklin Resources Inc+253K sh+$13.9M
- Deep Track Capital, LP−1M sh−$56.6M
- Braidwell LP−782K sh−$43.1M
- Caligan Partners LP−649K sh−$35.8M
- Cormorant Asset Management, LP−570K sh−$31.5M
- Stempoint Capital LP−999K sh−$29.8M
- Citadel Advisors LLC−933K sh−$27.8M
- EcoR1 Capital, LLC−389K sh−$21.4M
- Millennium Management LLC−338K sh−$18.7M
MBX institutional ownership FAQ
Who owns the most MBX stock?
In Q2 2026 13F filings the largest holder of MBX was Frazier Life Sciences Management, L.P., followed by Fmr LLC and Wellington Management Group LLP. Index fund managers are usually the biggest holders of large companies.
What percentage of MBX is owned by institutions?
Funds that file 13F reports held 115.2% of MBX's shares at Jun 30, 2026, compared with 110.1% a quarter earlier. That counts every manager with more than $100 million in US stocks.
Are hedge funds buying MBX?
In Q2 2026, 98 funds bought MBX (36 of them new positions) and 67 sold (20 sold out completely). Among well known investors, 0 added and 2 cut. Our fund sentiment for MBX is bullish.
What is MBX's institutional put/call ratio?
Funds reported $11M of MBX puts against $11M of calls, a put/call ratio of 1.00. Market makers and bank trading desks are left out, since their options are mostly hedges.
How current is this MBX ownership data?
13F filings show holdings at the end of each quarter and are due within 45 days, so positions can be up to six weeks old when they appear. We add each new filing within minutes, and the "filed so far" list shows funds that have already reported the next quarter.
For informational and educational purposes only. Not investment advice, and not a recommendation to buy or sell any security. Fund sentiment summarises what 13F filings show and is not a forecast. Holdings come from SEC Form 13F filings as reported and show positions at the end of the quarter, up to 45 days before the filing. A 13F leaves out short positions, cash, bonds and most foreign holdings. See all hedge fund holdings.