Institutional Holders (2026 Q1)
202 + investorsExplore institutional interest and hedge fund ownership dynamics. Analyze portfolio weights, new positions, and conviction trends in IRON. Verified SEC 13F-HR filings.
| # | Investor | % of Portfolio | Shares | Mkt Value |
|---|---|---|---|---|
| 1 | Atlas Venture Life Science Advisors, LLC | 12.25% | 1,513,875 | $96.8M |
| 2 | Foresite Capital Management V, LLC | 8.83% | 374,069 | $23.9M |
| 3 | Checkpoint Capital L.P. | 6.58% | 286,661 | $18.3M |
| 4 | Saturn V Capital Management LP | 5.21% | 449,926 | $28.8M |
| 5 | Palo Alto Investors LP | 3.93% | 401,719 | $25.7M |
| 6 | Opaleye Management Inc. | 3.55% | 421,000 | $26.9M |
| 7 | Lion Point Capital, LP | 3.10% | 8,100 | $518K |
| 8 | KVP Capital Advisors, LP | 2.78% | 58,250 | $3.7M |
| 9 | BVF INC/IL | 2.59% | 1,272,312 | $81.4M |
| 10 | TCG Crossover Management, LLC | 2.45% | 1,341,862 | $85.8M |
| 11 | Frazier Life Sciences Management, L.P. | 2.23% | 1,354,852 | $86.6M |
| 12 | Octagon Capital Advisors LP | 1.91% | 270,000 | $17.3M |
| 13 | Logos Global Management LP | 1.79% | 560,000 | $35.8M |
| 14 | Siren, L.L.C. | 1.75% | 988,401 | $63.2M |
| 15 | RA CAPITAL MANAGEMENT, L.P. | 1.66% | 2,450,221 | $156.7M |
| 16 | Catalio Capital Management, LP | 1.64% | 122,978 | $7.9M |
| 17 | NEXTBio Capital Management LP | 1.56% | 52,655 | $3.4M |
| 18 | ORBIMED ADVISORS LLC | 1.35% | 1,067,550 | $68.3M |
| 19 | SILVERARC CAPITAL MANAGEMENT, LLC | 1.28% | 196,028 | $12.5M |
| 20 | Vestal Point Capital, LP | 1.25% | 700,000 | $44.8M |
| 21 | Atle Fund Management AB | 1.03% | 107,255 | $3.2M |
| 22 | Bain Capital Life Sciences Investors, LLC | 0.81% | 141,234 | $9.0M |
| 23 | Bellevue Group AG | 0.70% | 459,314 | $29.4M |
| 24 | ARMISTICE CAPITAL, LLC | 0.61% | 536,000 | $34.3M |
| 25 | Sio Capital Management, LLC | 0.60% | 65,203 | $4.2M |
| Investor | Ownership History |
% of Portfolio | Prev % | Rank | Conviction | Avg Buy Price | 13F Score™ 3Y / 7Y | Sell Timing | Shares | Mkt Value | Change | Change % | Source | Quarter | Filed |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|