Gossamer Bio, Inc.
GOSS- Exchange
- Nasdaq
- Industry
- Pharmaceutical Preparations
- SEC CIK
- 0001728117
No open-market purchases or sales by Gossamer Bio, Inc. insiders were filed in the last 90 days; 170 institutions reported holding it in 13F filings for Q2 2026, worth $60.8M in total; HHLR Advisors (Hillhouse) is the only superinvestor holding it.
Holders of 5% or more of GOSS
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Gossamer Bio, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| Octagon Capital Advisors LP | 13G/A | 6.50%15.1M shares | −2.10 ppfrom 8.60% | Feb 5, 20252 filings | Feb 17, 2026 | SEC |
| BlackRock, Inc. | 13G/A | 6.50%15.1M shares | +1.20 ppfrom 5.30% | Jul 17, 20252 filings | Jan 21, 2026 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
11 Schedule 13D and 13G filings on Gossamer Bio, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Mar 27, 20269:31 AM ET | Vanguard Group Inc | 13G/A | 0.00%0 shares | −5.02 ppfrom 5.02%Below 5% | Mar 13, 2026 | SEC |
| Mar 24, 20264:48 PM ET | 683 Capital Management, LLCand 2 others | 13G/A | 3.90%9.33M shares | −1.33 ppfrom 5.23%Below 5% | Mar 18, 2026 | SEC |
| Mar 2, 202611:57 AM ET | 683 Capital Management, LLCand 2 others | 13G | 5.23%12.3M shares | New | Feb 23, 2026 | SEC |
| Feb 24, 20267:21 PM ET | Growth Equity Opportunities 18 VGE, LLCand 11 others | 13D/A | 1.70%4.07M shares | –Below 5% | Feb 23, 2026 | SEC |
| Feb 17, 20264:02 PM ET | Octagon Capital Advisors LPand 2 others | 13G/A | 6.50%15.1M shares | −2.10 ppfrom 8.60% | Dec 31, 2025 | SEC |
| Jan 21, 202612:30 PM ET | BlackRock, Inc. | 13G/A | 6.50%15.1M shares | +1.20 ppfrom 5.30% | Dec 31, 2025 | SEC |
| Jul 29, 20251:34 PM ET | Vanguard Group Inc | 13G | 5.02%11.4M shares | +0.60 ppfrom 4.42% | Jun 30, 2025 | SEC |
| Jul 17, 20257:54 PM ET | BlackRock, Inc. | 13G | 5.30%12.1M shares | New | Jun 30, 2025 | SEC |
| Feb 12, 20254:30 PM ET | Invus Global Management, LLCand 7 others | 13G/A | 2.80%6.26M shares | –Below 5% | Dec 31, 2024 | SEC |
| Feb 5, 20256:28 PM ET | Octagon Capital Advisors LPand 2 others | 13G | 8.60%19.6M shares | New | Dec 31, 2024 | SEC |
| Jan 30, 20259:57 PM ET | Vanguard Group Inc | 13G/A | 4.42%10.0M shares | –Below 5% | Dec 31, 2024 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Gossamer Bio, Inc. shares.
No Form 144 notices for Gossamer Bio, Inc. are on file.