44% buyers of institutions opening or closing positions this quarter
12 more exits than new buyers, ownership fell 73.54 percentage points vs the prior quarter, and 1 well-known fund manager in the top 25.
44% buyers of institutions opening or closing positions this quarter
126.4% institutional ownership
Kalehua Capital Management portfolio allocation
Institutional ownership vs Biotechnology peers
No Form 4 insider transactions on file
Latest positioning in GOSS across 13F flow, ownership shift, marquee holders, and holder-count growth.
Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in GOSS held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | 16.8M | $5.5M | -1.4% | 7.170% | 0.00% |
| 2 | AQR CAPITAL MANAGEMENT LLC | 10.1M | $3.3M | +804.8% | 4.315% | 0.00% |
| 3 | VANGUARD CAPITAL MANAGEMENT LLC | 9.4M | $3.1M | — | 4.003% | 0.00% |
| 4 | ARCH Venture Management, LLC | 8.1M | $2.6M | 0.0% | 3.433% | 0.39% |
| 5 | Octagon Capital Advisors LP | 7.8M | $2.5M | -44.3% | 3.302% | 0.28% |
| 6 | Kalehua Capital Management LLC | 7.5M | $2.5M | — | 3.184% | 2.07% |
| 7 | Samsara BioCapital, LLC | 7.2M | $2.4M | 0.0% | 3.077% | 0.23% |
| 8 | BALYASNY ASSET MANAGEMENT LLC | 5.9M | $1.9M | +290.5% | 2.523% | 0.00% |
| 9 | Siren, L.L.C. | 5.2M | $1.7M | 0.0% | 2.220% | 0.05% |
| 10 | 683 Capital Management, LLC | 5.0M | $1.6M | -8.9% | 2.130% | 0.09% |
| 11 | HHLR ADVISORS, LTD. | 5.0M | $1.6M | 0.0% | 2.119% | 0.10% |
| 12 | GEODE CAPITAL MANAGEMENT, LLC | 4.9M | $1.6M | +1.4% | 2.105% | 0.00% |
| 13 | Qube Research & Technologies Ltd | 4.9M | $1.6M | +809.7% | 2.095% | 0.00% |
| 14 | TWO SIGMA INVESTMENTS, LP | 4.8M | $1.6M | +40.7% | 2.037% | 0.00% |
| 15 | STATE STREET CORP | 4.4M | $1.4M | -52.9% | 1.870% | 0.00% |
| 16 | Corient Private Wealth LLC | 4.0M | $1.3M | +3.6% | 1.698% | 0.00% |
| 17 | Squarepoint Ops LLC | 3.4M | $1.1M | +1433.8% | 1.448% | 0.00% |
| 18 | BANK OF AMERICA CORP /DE/ | 3.2M | $1.0M | +66.5% | 1.352% | 0.00% |
| 19 | BARCLAYS PLC | 3.1M | $1.0M | +431.8% | 1.306% | 0.00% |
| 20 | VANGUARD PORTFOLIO MANAGEMENT LLC | 2.2M | $711K | — | 0.921% | 0.00% |
| 21 | Alyeska Investment Group, L.P. | 2.1M | $674K | +125.7% | 0.874% | 0.00% |
| 22 | UBS Group AG | 1.9M | $620K | +6.3% | 0.803% | 0.00% |
| 23 | ALLIANCEBERNSTEIN L.P. | 190K | $590K | 0.0% | 0.081% | 0.00% |
| 24 | Ensign Peak Advisors, Inc | 1.7M | $559K | — | 0.725% | 0.00% |
| 25 | JACOBS LEVY EQUITY MANAGEMENT, INC | 1.7M | $557K | -22.2% | 0.722% | 0.00% |
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 GOSS — a direct measure of their conviction.
Filings activity in GOSS during Q1 2026, grouped by how each filer changed its position.
Institutions that opened a new GOSS position in Q1 2026
Institutions that fully closed their GOSS position in Q1 2026
8 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 | 179 | 6.3% | 126.45% | 73.54 pp | $53M | 91% |
| Q4 2025 | 191 | +19% | 199.99% | +0.00 pp | $568M | +23% |
| Q3 2025 | 160 | +29% | 199.99% | +0.00 pp | $462M | +121% |
| Q2 2025 | 124 | +3.3% | 199.99% | +0.00 pp | $210M | +16% |
| Q1 2025 | 120 | +18% | 199.99% | +0.00 pp | $180M | +24% |
| Q4 2024 | 102 | +3.0% | 199.99% | +0.00 pp | $145M | 2.5% |
| Q3 2024 | 99 | +6.5% | 199.99% | +0.00 pp | $149M | 8.5% |
| Q2 2024 | 93 | — | 199.99% | — | $162M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
No recent Form 4 insider transactions on file for GOSS.
Quick answers to the most common questions about buying GOSS stock.
Based on Q1 2026 13F filings, institutional ownership of Gossamer Bio, Inc. stands at 126.4%, held across 179 reporting institutions.
BlackRock, Inc. is the largest reported institutional holder of GOSS, with approximately 16,826,695 shares worth $0.01B as of Q1 2026.
Yes — 1 widely-followed marquee investor appear among the top 25 institutional holders of GOSS, including TWO SIGMA INVESTMENTS, LP.
Our composite Smart Money Score for GOSS is 33 out of 100 (Bearish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
45 institutions opened new positions in GOSS during Q1 2026, while 57 fully exited. 9 added to existing positions and 124 trimmed.
GOSS institutional ownership fell by 73.54 percentage points quarter-over-quarter, with a net change of -12 holders.
The top 10 institutions account for 51.8% of all reported 13F value in GOSS, and the top 25 account for 82.3%.
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.