Gossamer Bio, Inc. (GOSS) Ownership
GOSS ownership summary
as of October 18, 2026- Institutions
- 85.8% of shares outstanding
- Insiders
- 1.43% of shares outstanding
- Shares outstanding
- 6.1M
- Float
- 3.8M shares available to trade
- Short interest
- 20.53% 1.2M shares short
- Days to cover
- 4.57 short interest up 30.5% vs prior month
- Institutions 85.80%
- Insiders 1.43%
- Other investors 12.77%
GOSS top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | D. E. Shaw & Co LP | 8.37% | 41.0M | $359.2M | +40.6M (+10,417.7%) | June 30, 2026 |
| 2 | DeepCurrents Investment Group LLC | 7.70% | 37.7M | $330.3M | +37.7M (0.0%) | June 30, 2026 |
| 3 | Context Capital Management LLC | 5.92% | 28.9M | $253.9M | +28.9M (0.0%) | June 30, 2026 |
| 4 | Worth Venture Partners, LLC | 5.11% | 25.0M | $219.4M | +25.0M (0.0%) | June 30, 2026 |
| 5 | Kalehua Capital Management LLC | 4.56% | 22.3M | $195.6M | +4.6M (+25.9%) | June 30, 2026 |
| 6 | AQR Capital Management LLC | 3.19% | 15.6M | $137.1M | +5.5M (+54.3%) | June 30, 2026 |
| 7 | GSA Capital Partners LLP | 3.06% | 15.0M | $131.4M | +11.7M (+360.5%) | June 30, 2026 |
| 8 | Wolverine Asset Management LLC | 2.64% | 12.9M | $113.1M | +12.9M (0.0%) | June 30, 2026 |
| 9 | Renaissance Technologies Corp | 2.38% | 11.6M | $102.0M | +10.4M (+854.9%) | June 30, 2026 |
| 10 | Vanguard Capital Management, LLC | 1.92% | 9.4M | $82.6M | +21,430 (+0.2%) | June 30, 2026 |
| 11 | ARCH VENTURE CORP | 1.65% | 8.1M | $70.7M | — | June 30, 2026 |
| 12 | Barclays PLC | 1.60% | 7.8M | $68.7M | +4.8M (+155.5%) | June 30, 2026 |
| 13 | Octagon Capital Advisors LP | 1.58% | 7.8M | $68.0M | — | June 30, 2026 |
| 14 | BlackRock Inc | 1.57% | 7.7M | $67.3M | −9.2M (−54.4%) | June 30, 2026 |
| 15 | Arrowstreet Capital Limited Partnership | 1.55% | 7.6M | $66.4M | +7.6M (0.0%) | June 30, 2026 |
| 16 | Two Sigma Investments LLC | 1.52% | 7.4M | $65.2M | +2.7M (+55.5%) | June 30, 2026 |
| 17 | Samsara BioCapital, LLC | 1.48% | 7.2M | $63.3M | — | June 30, 2026 |
| 18 | Qube Research & Technologies | 1.44% | 7.1M | $62.0M | +2.1M (+43.7%) | June 30, 2026 |
| 19 | CI Private Wealth LLC | 1.15% | 5.6M | $49.4M | +1.6M (+41.3%) | June 30, 2026 |
| 20 | Siren, L.L.C. | 1.06% | 5.2M | $45.7M | — | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 15 holders added 196.1M shares and 1 cut 9.2M.
GOSS top mutual fund and ETF holders
18 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 1.41% | 6.9M | $60.6M | — | August 31, 2026 |
| 2 | Fidelity Nasdaq Composite Index | 0.54% | 2.6M | $23.2M | +2.5M (+1,781.7%) | August 31, 2026 |
| 3 | Abante Quant Value FI | 0.38% | 1.8M | $16.2M | +400,000 (+27.6%) | August 31, 2026 |
| 4 | Fidelity Extended Market Index | 0.32% | 1.6M | $13.9M | +1.6M (+10,531.5%) | August 31, 2026 |
| 5 | Vanguard Health Care ETF | 0.27% | 1.3M | $11.6M | +769,639 (+140.2%) | August 31, 2026 |
| 6 | Xtrackers S&P 500 Swap ETF 1C | 0.22% | 1.1M | $9.6M | −8,102 (−0.7%) | December 31, 2025 |
| 7 | Federated Hermes Kaufmann Small Cap A | 0.16% | 766K | $6.7M | — | June 30, 2026 |
| 8 | Fidelity Total Market Index | 0.08% | 381K | $3.3M | — | August 31, 2026 |
| 9 | BlackRock Health Sciences Opps Inv A | 0.07% | 365K | $3.2M | — | August 31, 2026 |
| 10 | Fidelity Series Total Market Index | 0.06% | 300K | $2.6M | — | August 31, 2026 |
| 11 | Goldman Sachs Absolute Ret Trckr Instl | 0.05% | 267K | $2.3M | +235,798 (+749.8%) | June 30, 2026 |
| 12 | Vanguard Balanced Index Inv | 0.03% | 154K | $1.4M | — | August 31, 2026 |
| 13 | Fidelity ZERO Extended Market Index | 0.03% | 147K | $1.3M | +71,755 (+96.0%) | August 31, 2026 |
| 14 | Fidelity ZERO Total Market Index | 0.02% | 100K | $876,790 | — | August 31, 2026 |
| 15 | iShares Biotechnology ETF | 0.72% | 44K | $383,775 | −328 (−0.7%) | September 30, 2026 |
| 16 | iShares Nasdaq US Biotech ETF USD Acc | 0.13% | 7,789 | $68,310 | +64 (+0.8%) | September 30, 2026 |
| 17 | Invesco RAFI US 1500 Small-Mid ETF | 0.11% | 6,968 | $61,109 | — | September 30, 2026 |
| 18 | Eventide Small Cap ETF | 0.05% | 3,118 | $27,345 | — | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
GOSS insider transactions
latest 7| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2024-06-24 | Richard Aranda | Sell | $0.66 | 1,908 | $1,259 |
| 2024-06-21 | Faheem Hasnain | Buy | $0.67 | 372,000 | $249,240 |
| 2024-03-27 | Bryan Giraudo | Sell | $1.16 | 6,430 | $7,459 |
| 2024-03-27 | Faheem Hasnain | Sell | $1.16 | 23,172 | $26,880 |
| 2024-03-18 | Richard Aranda | Sell | $1.33 | 4,018 | $5,344 |
| 2023-11-13 | Bryan Giraudo | Buy | $0.56 | 200,000 | $112,000 |
| 2023-06-22 | Richard Aranda | Sell | $1.29 | 1,814 | $2,340 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
GOSS shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns GOSS
Institutional investors own 85.8% of Gossamer Bio's shares and insiders 1.43%. The largest holder is D. E. Shaw & Co LP with 8.37% of the shares (41.0M), as of June 30, 2026. Among the top 20 institutions, 15 added shares and 1 reduced their stake in the latest filings. Short interest is 20.53% of the float, or 4.57 days of average trading volume. The share count rose 2,373.9% since 2017.
Related: GOSS analyst forecast, GOSS key metrics. See the GOSS stock overview for the latest quote and news.
GOSS ownership FAQ
Who owns the most Gossamer Bio stock?
The largest shareholders of Gossamer Bio are D. E. Shaw & Co LP (8.37%), DeepCurrents Investment Group LLC (7.70%), Context Capital Management LLC (5.92%), Worth Venture Partners, LLC (5.11%), Kalehua Capital Management LLC (4.56%).
What percentage of Gossamer Bio is owned by institutions?
Institutions hold 85.8% of Gossamer Bio's shares outstanding; insiders hold 1.43%.
Which funds own Gossamer Bio?
The largest fund holders of Gossamer Bio are Vanguard MStar Total Stk Mkt Idx Invest (1.41%), Fidelity Nasdaq Composite Index (0.54%), Abante Quant Value FI (0.38%), Fidelity Extended Market Index (0.32%), Vanguard Health Care ETF (0.27%).
What is Gossamer Bio's short interest?
1.2M shares of Gossamer Bio were sold short, 20.53% of the float; at the average daily volume it would take 4.57 days to cover.
Are insiders buying or selling Gossamer Bio?
Of the latest 7 reported insider transactions in Gossamer Bio (since June 22, 2023), 2 were purchases and 5 were sales.
How many shares of Gossamer Bio are outstanding?
Gossamer Bio has 6.1M shares outstanding, of which 3.8M are in the public float.