GOSSAMER BIO INC GOSS
COM · Common Stock · CUSIP 38341P102
Company in San Diego, United States
- SectorHealth care
- IndustryPharmaceutical Preparations
- HeadquartersSan Diego, CA
- Founded2015
- Websitegossamerbio.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once. Holder counts are more reliable. Shares outstanding: 227.2m as of 2025-03-06, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $1.10. Options: 11 managers hold calls ($2.9m notional), 4 hold puts ($117.4k).
Trends to Q1 2025
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 160 |
| Q4 2022 | 120 |
| Q1 2023 | 112 |
| Q2 2023 | 100 |
| Q3 2023 | 97 |
| Q4 2023 | 99 |
| Q1 2024 | 110 |
| Q2 2024 | 95 |
| Q3 2024 | 101 |
| Q4 2024 | 106 |
| Q1 2025 | 120 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q2 2023 | 32 | 68 |
| Q3 2023 | 62 | 53 |
| Q4 2023 | 54 | 43 |
| Q1 2024 | 53 | 46 |
| Q2 2024 | 43 | 54 |
| Q3 2024 | 39 | 41 |
| Q4 2024 | 44 | 40 |
| Q1 2025 | 58 | 39 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q2 2024 | $591.1k | $575.9k | 0.97 |
| Q3 2024 | $784.8k | $579.3k | 0.74 |
| Q4 2024 | $1.1m | $598.0k | 0.54 |
| Q1 2025 | $2.9m | $117.4k | 0.04 |
Biggest buyers
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | +2.3m |
| ACADIAN ASSET MANAGEMENT LLC | Added | +1.3m |
| GOLDMAN SACHS GROUP INC | Added | +825.0k |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP | New | +803.8k |
| Atom Investors LP | New | +702.0k |
| Focus Partners Wealth | New | +700.0k |
| JANE STREET GROUP, LLC | Added | +670.6k |
| HRT FINANCIAL LP | New | +389.5k |
| TWO SIGMA INVESTMENTS, LP | Added | +384.1k |
| OMERS ADMINISTRATION Corp | New | +351.6k |
Biggest sellers
| Alyeska Investment Group, L.P. | Reduced | -4.6m |
| PLATINUM INVESTMENT MANAGEMENT LTD | Reduced | -1.4m |
| JACOBS LEVY EQUITY MANAGEMENT, INC | Reduced | -1.3m |
| Eversept Partners, LP | Reduced | -1.1m |
| MILLENNIUM MANAGEMENT LLC | Reduced | -908.0k |
| 683 Capital Management, LLC | Reduced | -875.0k |
| MARSHALL WACE, LLP | Reduced | -820.7k |
| MACKENZIE FINANCIAL CORP | Reduced | -547.0k |
| Monaco Asset Management SAM | Reduced | -522.5k |
| DAFNA Capital Management LLC | Reduced | -501.4k |
Biggest calls
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $1.1m970.5k shares |
| DIADEMA PARTNERS LP | Added | $907.3k824.8k shares |
| SIMPLEX TRADING, LLC | Added | $394.0k358.6k shares |
| Caption Management, LLC | New | $220.0k200.0k shares |
| GROUP ONE TRADING LLC | Reduced | $87.9k79.9k shares |
| Persistent Asset Partners Ltd | Added | $80.0k1.9k shares |
| CITADEL ADVISORS LLC | Reduced | $75.2k68.4k shares |
| Exome Asset Management LLC | New | $47.5k100.0k shares |
| Callan Capital, LLC | Added | $31.5k30.0k shares |
| WOLVERINE TRADING, LLC | Reduced | $21.6k18.5k shares |
Biggest puts
| CITADEL ADVISORS LLC | Reduced | $63.6k57.8k shares |
| SIMPLEX TRADING, LLC | Reduced | $40.0k36.5k shares |
| GROUP ONE TRADING LLC | Added | $13.9k12.6k shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| 683 Capital Management, LLC 13G · passive investor +6.1 pts · filed 2026-06-11 | 10.0% |
| Context Capital Management, LLC 13G · passive investor new · filed 2026-06-09 | 9.9% |
| DeepCurrents Investment Group LLC 13G · passive investor new · filed 2026-06-11 | 7.7% |
| D. E. SHAW & CO, L.P. 13D · may seek influence -1.1 pts · filed 2026-08-24 | 6.0% |
| Opaleye Management Inc. 13G · passive investor new · filed 2026-07-29 | 5.1% |
Fell to 5% or below in the last year: BlackRock, Inc. (1.0%, 2026-07-29), Octagon Capital Advisors LP (3.8%, 2026-05-14), VANGUARD GROUP INC (0.0%, 2026-03-27), Growth Equity Opportunities 18 VGE, LLC (1.7%, 2026-02-24)
Insider purchases and sales in Q1 2025
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q2 2023 | 1 | $56.1k | 1 | $2.3k | — |
| Q3 2023 | 0 | — | 0 | — | — |
| Q4 2023 | 2 | $137.3k | 0 | — | — |
| Q1 2024 | 0 | — | 5 | $39.7k | — |
| Q2 2024 | 3 | $323.2k | 1 | $1.3k | — |
| Q3 2024 | 0 | — | 0 | — | — |
| Q4 2024 | 0 | — | 0 | — | — |
| Q1 2025 | 0 | — | 0 | — | — |
None reported in Q1 2025.
Holders, Q1 2025
| Manager | Shares | Change |
|---|---|---|
| Octagon Capital Advisors LP 3.97% of their portfolio | 18.4m $20.2m | Unchanged |
| NEA Management Company, LLC 1.53% of their portfolio | 18.1m $19.9m | Unchanged |
| VANGUARD GROUP INC 0.00% of their portfolio | 10.1m $11.1m | Added +49.7k |
| ARCH Venture Management, LLC 4.26% of their portfolio | 8.1m $8.8m | Unchanged |
| FMR LLC 0.00% of their portfolio | 7.6m $8.4m | Reduced -340.0k |
| ACADIAN ASSET MANAGEMENT LLC 0.02% of their portfolio | 6.4m $7.0m | Added +1.3m |
| SILVERARC CAPITAL MANAGEMENT, LLC 1.45% of their portfolio | 6.3m $7.0m | Added +148.8k |
| Palo Alto Investors LP 1.31% of their portfolio | 6.3m $6.9m | Reduced -200 |
| SAMSARA BIOCAPITAL, LLC 1.20% of their portfolio | 6.1m $6.7m | Unchanged |
| 683 Capital Management, LLC 0.68% of their portfolio | 6.1m $6.7m | Reduced -875.0k |
| Siren, L.L.C. 0.32% of their portfolio | 5.2m $5.7m | Unchanged |
| HHLR ADVISORS, LTD. 0.15% of their portfolio | 5.0m $5.5m | Unchanged |
| Monaco Asset Management SAM 2.70% of their portfolio | 4.8m $5.3m | Reduced -522.5k |
| Opaleye Management Inc. 1.05% of their portfolio | 4.3m $4.7m | Reduced -202.6k |
| Alyeska Investment Group, L.P. 0.02% of their portfolio | 4.2m $4.6m | Reduced -4.6m |
| Eversept Partners, LP 0.49% of their portfolio | 3.9m $4.3m | Reduced -1.1m |
| Corient Private Wealth LP 0.01% of their portfolio | 3.4m $3.7m | Unchanged |
| Rock Springs Capital Management LP 0.21% of their portfolio | 3.3m $3.6m | Unchanged |
| BlackRock, Inc. 0.00% of their portfolio | 3.1m $3.4m | Added +43.6k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.01% of their portfolio | 2.9m $3.2m | Added +2.3m |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 2.7m $2.9m | Reduced -908.0k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 2.3m $2.5m | Added +22.0k |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 2.1m $2.3m | Unchanged |
| PLATINUM INVESTMENT MANAGEMENT LTD 0.11% of their portfolio | 1.7m $1.9m | Reduced -1.4m |
| MARSHALL WACE, LLP 0.00% of their portfolio | 1.7m $1.9m | Reduced -820.7k |
| RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio | 1.6m $1.7m | Reduced -143.3k |
| Laurion Capital Management LP 0.13% of their portfolio | 1.6m $1.7m | Added +63.4k |
| TWO SIGMA ADVISERS, LP 0.00% of their portfolio | 1.3m $1.4m | Added +129.7k |
| TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio | 1.3m $1.4m | Added +384.1k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 1.1m $1.3m | Reduced -103.0k |
| Exome Asset Management LLC 1.08% of their portfolio | 1.1m $1.2m | Unchanged |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 939.6k $1.0m | Added +825.0k |
| DAFNA Capital Management LLC 0.28% of their portfolio | 907.9k $998.6k | Reduced -501.4k |
| Qube Research & Technologies Ltd 0.00% of their portfolio | 895.5k $985.1k | Added +199.6k |
| STATE STREET CORP 0.00% of their portfolio | 882.7k $970.9k | Added +114.2k |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.00% of their portfolio | 803.8k $884.2k | New |
| Woodline Partners LP 0.01% of their portfolio | 728.5k $801.3k | Unchanged |
| Atom Investors LP 0.09% of their portfolio | 702.0k $772.2k | New |
| Focus Partners Wealth 0.00% of their portfolio | 700.0k $770.0k | New |
| GSA CAPITAL PARTNERS LLP 0.07% of their portfolio | 695.6k $765.0k | Reduced -166.9k |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 683.4k $751.8k | Added +670.6k |
| Allostery Investments LP 0.97% of their portfolio | 613.0k $674.3k | Unchanged |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.02% of their portfolio | 560.9k $617.0k | Added +19.9k |
| HIGHBRIDGE CAPITAL MANAGEMENT LLC 0.02% of their portfolio | 497.7k $547.5k | Reduced -100.0k |
| MORGAN STANLEY 0.00% of their portfolio | 459.5k $505.5k | Added +311.0k |
| Opti Capital Management, LP 0.03% of their portfolio | 414.2k $455.6k | Added +231.8k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 410.1k $451.1k | Reduced -1.2k |
| HRT FINANCIAL LP 0.00% of their portfolio | 389.5k $428.0k | New |
| PRELUDE CAPITAL MANAGEMENT, LLC 0.04% of their portfolio | 376.8k $414.5k | Reduced -38.0k |
| MACKENZIE FINANCIAL CORP 0.00% of their portfolio | 352.5k $387.7k | Reduced -547.0k |
| OMERS ADMINISTRATION Corp 0.00% of their portfolio | 351.6k $386.8k | New |
| SILVERBACK ASSET MANAGEMENT LLC 0.06% of their portfolio | 350.0k $385.0k | New |
| SMITH, MOORE & CO. 0.03% of their portfolio | 300.0k $330.0k | Unchanged |
| Balyasny Asset Management L.P. 0.00% of their portfolio | 289.3k $318.2k | New |
| JACOBS LEVY EQUITY MANAGEMENT, INC 0.00% of their portfolio | 282.3k $310.5k | Reduced -1.3m |
| DIADEMA PARTNERS LP 0.24% of their portfolio | 269.6k $296.5k | Added +51.6k |
| VICTORY CAPITAL MANAGEMENT INC 0.00% of their portfolio | 264.1k $290.5k | Reduced -1.3k |
| BARCLAYS PLC 0.00% of their portfolio | 245.1k $269.6k | Added +245.0k |
| ADAR1 Capital Management, LLC 0.05% of their portfolio | 227.2k $250.0k | Reduced -68.4k |
| UBS Group AG 0.00% of their portfolio | 220.3k $242.3k | Added +201.2k |
| Squarepoint Ops LLC 0.00% of their portfolio | 217.9k $239.7k | Added +146.0k |
| GROUP ONE TRADING LLC 0.01% of their portfolio | 207.7k $228.5k | Added +133.1k |
| Schonfeld Strategic Advisors LLC 0.00% of their portfolio | 201.7k $221.9k | Added +47.0k |
| Jain Global LLC 0.00% of their portfolio | 199.9k $219.9k | New |
| Cubist Systematic Strategies, LLC 0.00% of their portfolio | 194.0k $213.4k | New |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 163.8k $180.2k | Added +79.0k |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 156.9k $172.6k | Added +16.9k |
| Birchview Capital, LP 0.13% of their portfolio | 138.2k $152.0k | Reduced -138.2k |
| Sequoia Financial Advisors, LLC 0.00% of their portfolio | 118.5k $130.3k | Unchanged |
| Quantessence Capital LLC 0.03% of their portfolio | 118.3k $130.2k | New |
| LMR Partners LLP 0.00% of their portfolio | 115.6k $127.2k | New |
| ExodusPoint Capital Management, LP 0.00% of their portfolio | 105.1k $116.0k | New |
| Jefferies Financial Group Inc. 0.00% of their portfolio | 100.0k $110.0k | Unchanged |
| Diametric Capital, LP 0.13% of their portfolio | 96.1k $105.7k | Reduced -127.7k |
| Point72 Asia (Singapore) Pte. Ltd. 0.02% of their portfolio | 83.1k $91.4k | New |
| Financial Advocates Investment Management 0.01% of their portfolio | 78.6k $86.5k | Unchanged |
| Velan Capital Investment Management LP 0.08% of their portfolio | 75.0k $82.5k | Unchanged |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 64.8k $72.0k | Unchanged |
| Persistent Asset Partners Ltd 0.06% of their portfolio | 62.0k $68.2k | Reduced -3.9k |
| Catalyst Funds Management Pty Ltd 0.01% of their portfolio | 52.0k $57.2k | New |
| CHOREO, LLC 0.00% of their portfolio | 48.1k $52.9k | Unchanged |
| PRUDENTIAL FINANCIAL INC 0.00% of their portfolio | 47.0k $51.8k | Unchanged |
| HB Wealth Management, LLC 0.00% of their portfolio | 46.7k $51.4k | Added +9.0k |
| TUDOR INVESTMENT CORP ET AL 0.00% of their portfolio | 46.5k $51.1k | Unchanged |
| LAZARD ASSET MANAGEMENT LLC 0.00% of their portfolio | 43.8k $48.0k | Reduced -63.7k |
| Invesco Ltd. 0.00% of their portfolio | 43.7k $48.1k | New |
| COMMONWEALTH EQUITY SERVICES, LLC 0.00% of their portfolio | 42.1k $46.0k | Added +7.6k |
| Hudson Bay Capital Management LP 0.00% of their portfolio | 36.9k $40.6k | New |
| Virtu Financial LLC 0.00% of their portfolio | 35.0k $38.0k | New |
| US BANCORP \DE\ 0.00% of their portfolio | 33.5k $36.8k | Reduced -6.2k |
| Sivia Capital Partners, LLC 0.02% of their portfolio | 30.0k $33.0k | Added +2.0k |
| Graham Capital Management, L.P. 0.00% of their portfolio | 29.0k $31.9k | Reduced -6.0k |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 27.5k $30.2k | Added +51 |
| SILVERCREST ASSET MANAGEMENT GROUP LLC 0.00% of their portfolio | 26.2k $28.8k | Unchanged |
| Brevan Howard Capital Management LP 0.00% of their portfolio | 23.7k $26.0k | New |
| Traynor Capital Management, Inc. 0.00% of their portfolio | 23.3k $25.6k | Added +9.3k |
| Clearstead Advisors, LLC 0.00% of their portfolio | 22.0k $24.2k | Unchanged |
| Bank of New York Mellon Corp 0.00% of their portfolio | 20.2k $22.2k | Reduced -1 |
| Cambridge Investment Research Advisors, Inc. 0.00% of their portfolio | 19.3k $21.0k | Added +3.3k |
| Vanguard Personalized Indexing Management, LLC 0.00% of their portfolio | 17.0k $18.7k | Added +2.5k |