SEPTERNA INC SEPN
COM · Common Stock · CUSIP 81734D104
- SectorHealth care
- IndustryPharmaceutical Preparations
- HeadquartersSouth San Francisco, CA
- 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 ($224.9k this quarter). Holder counts are more reliable. Shares outstanding: 46.7m as of 2026-08-05, 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 ≈ $33.48. Options: 6 managers hold calls ($35.0m notional), 6 hold puts ($13.3m).
Trends to Q2 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q4 2024 | 72 |
| Q1 2025 | 72 |
| Q2 2025 | 90 |
| Q3 2025 | 82 |
| Q4 2025 | 122 |
| Q1 2026 | 124 |
| Q2 2026 | 154 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q1 2025 | 44 | 29 |
| Q2 2025 | 56 | 25 |
| Q3 2025 | 42 | 32 |
| Q4 2025 | 71 | 32 |
| Q1 2026 | 66 | 54 |
| Q2 2026 | 95 | 48 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2025 | $1.7m | $14.0m | 8.22 |
| Q4 2025 | $2.3m | $5.0m | 2.18 |
| Q1 2026 | $1.8m | $0 | 0.00 |
| Q2 2026 | $35.0m | $13.3m | 0.38 |
Biggest buyers
| LOOMIS SAYLES & CO L P | New | +624.8k |
| ALGERT GLOBAL LLC | Added | +376.5k |
| Catalio Capital Management, LP | Added | +241.8k |
| First Light Asset Management, LLC | Added | +230.4k |
| Longaeva Partners L.P. | Added | +223.6k |
| Woodline Partners LP | New | +185.5k |
| GOLDMAN SACHS GROUP INC | Added | +156.3k |
| TWO SIGMA INVESTMENTS, LP | Added | +145.5k |
| PRIMECAP MANAGEMENT CO/CA/ | Added | +118.5k |
| Balyasny Asset Management L.P. | Added | +113.8k |
Biggest sellers
| BVF INC/IL | Sold out | -1.4m |
| Venrock Adviser, LLC | Sold out | -506.1k |
| ADAR1 Capital Management, LLC | Reduced | -149.1k |
| Checkpoint Capital L.P. | Sold out | -100.3k |
| Siren, L.L.C. | Reduced | -100.0k |
| MILLENNIUM MANAGEMENT LLC | Reduced | -73.5k |
| Invesco Ltd. | Reduced | -58.8k |
| HUSSMAN STRATEGIC ADVISORS, INC. | Reduced | -42.0k |
| MARSHALL WACE, LLP | Sold out | -39.8k |
| Jump Financial, LLC | Reduced | -32.8k |
Biggest calls
| Caption Management, LLC | New | $14.7m440.0k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $8.8m262.0k shares |
| TUDOR INVESTMENT CORP ET AL | New | $6.7m200.0k shares |
| CITADEL ADVISORS LLC | New | $2.7m81.8k shares |
| JANE STREET GROUP, LLC | New | $1.9m57.2k shares |
| SIMPLEX TRADING, LLC | Added | $137.3k4.1k shares |
Biggest puts
| Caption Management, LLC | New | $6.7m200.0k shares |
| TUDOR INVESTMENT CORP ET AL | New | $3.3m100.0k shares |
| DIADEMA PARTNERS LP | New | $2.0m59.7k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | New | $1.1m33.9k shares |
| SIMPLEX TRADING, LLC | New | $83.7k2.5k shares |
| Persistent Asset Partners Ltd | New | $18.2k152 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 |
|---|---|
| Third Rock Ventures V, L.P. 13G · exempt (held before listing) no change · filed 2025-05-09 | 14.0% |
| RA CAPITAL MANAGEMENT, L.P. 13D · may seek influence filed 2026-08-14 | 11.8% |
| DRIEHAUS CAPITAL MANAGEMENT LLC 13G · institution -0.6 pts · filed 2026-08-14 | 9.8% |
Fell to 5% or below in the last year: BIOTECHNOLOGY VALUE FUND L P (3.8%, 2026-02-17)
Insider purchases and sales since 1 Apr 2026
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 |
|---|---|---|---|---|---|
| Q4 2024 | 1 | $75.1m | 0 | — | — |
| Q1 2025 | 3 | $934.4k | 0 | — | — |
| Q2 2025 | 0 | — | 0 | — | — |
| Q3 2025 | 0 | — | 0 | — | — |
| Q4 2025 | 0 | — | 1 | $63.2k | — |
| Q1 2026 | 0 | — | 2 | $2.1m | $2.1m |
| Q2 2026 | 0 | — | 3 | $1.5m | $1.5m |
| Q3 2026 | 0 | — | 3 | $65.0m | $1.6m |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2026-09-01 | Long Daniel D. SVP, Drug Discovery | Sold plan | $126.1k3.3k shares |
| 2026-08-12 | RA Capital Healthcare Fund LP +4 Director · See footnotes | Sold | $63.5m1.5m shares |
| 2026-08-11 | Bhatt Elizabeth President and COO | Sold plan | $1.1m25.0k shares |
| 2026-08-03 | Long Daniel D. SVP, Drug Discovery | Sold plan | $114.9k3.3k shares |
| 2026-07-15 | Bhatt Elizabeth President and COO | Sold plan | $136.0k4.0k shares |
| 2026-07-01 | Long Daniel D. SVP, Drug Discovery | Sold plan | $114.5k3.3k shares |
| 2026-06-29 | Shaikhly Samira Chief People Officer | Sold plan | $76.6k2.2k shares |
| 2026-06-22 | Long Daniel D. SVP, Drug Discovery | Sold plan | $532.6k15.0k shares |
| 2026-06-12 | Shaikhly Samira Chief People Officer | Sold plan | $219.2k6.2k shares |
| 2026-06-01 | Shaikhly Samira Chief People Officer | Sold plan | $171.7k5.9k shares |
| 2026-05-26 | Shaikhly Samira Chief People Officer | Sold plan | $354.6k11.8k shares |
| 2026-04-15 | Bhatt Elizabeth President and COO | Sold plan | $97.4k4.0k shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| RA CAPITAL MANAGEMENT, L.P. 2.04% of their portfolio | 7.0m $234.3m | Unchanged |
| TRV GP V, LLC 41.78% of their portfolio | 6.2m $208.2m | Unchanged |
| Driehaus Capital Management LLC 0.86% of their portfolio | 4.4m $148.5m | Added +37.5k |
| TRV GP VI, LLC 60.72% of their portfolio | 4.2m $141.0m | Unchanged |
| SAMSARA BIOCAPITAL, LLC 8.66% of their portfolio | 3.1m $105.5m | Unchanged |
| GOLDMAN SACHS GROUP INC 0.01% of their portfolio | 3.1m $102.6m | Added +156.3k |
| BlackRock, Inc. 0.00% of their portfolio | 1.9m $64.7m | Added +109.9k |
| Siren, L.L.C. 1.29% of their portfolio | 1.9m $63.6m | Reduced -100.0k |
| Avoro Capital Advisors LLC 0.40% of their portfolio | 1.3m $44.8m | Unchanged |
| Jupiter Topco LLC 0.02% of their portfolio | 1.3m $43.7m | First filing |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 1.2m $40.9m | Added +24.7k |
| PRIMECAP MANAGEMENT CO/CA/ 0.02% of their portfolio | 1.2m $39.1m | Added +118.5k |
| First Light Asset Management, LLC 1.96% of their portfolio | 963.3k $32.3m | Added +230.4k |
| ADAR1 Capital Management, LLC 1.48% of their portfolio | 940.7k $31.5m | Reduced -149.1k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 679.2k $22.8m | Added +34.0k |
| STATE STREET CORP 0.00% of their portfolio | 652.6k $21.9m | Added +21.2k |
| LOOMIS SAYLES & CO L P 0.03% of their portfolio | 624.8k $20.9m | New |
| Casdin Capital, LLC 0.93% of their portfolio | 553.3k $18.5m | Unchanged |
| Catalio Capital Management, LP 3.37% of their portfolio | 536.2k $18.0m | Added +241.8k |
| ALGERT GLOBAL LLC 0.16% of their portfolio | 397.5k $13.3m | Added +376.5k |
| Kalehua Capital Management LLC 4.16% of their portfolio | 389.1k $13.0m | Unchanged |
| Balyasny Asset Management L.P. 0.02% of their portfolio | 350.4k $11.7m | Added +113.8k |
| Longaeva Partners L.P. 0.29% of their portfolio | 298.2k $10.0m | Added +223.6k |
| Soleus Capital Management, L.P. 0.32% of their portfolio | 275.0k $9.2m | Unchanged |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 230.2k $7.7m | Added +35.1k |
| Universal- Beteiligungs- und Servicegesellschaft mbH 0.01% of their portfolio | 222.7k $7.5m | Reduced -1.3k |
| TWO SIGMA INVESTMENTS, LP 0.01% of their portfolio | 220.9k $7.4m | Added +145.5k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 201.1k $6.7m | Added +36.6k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 187.0k $6.3m | Added +5.5k |
| Woodline Partners LP 0.02% of their portfolio | 185.5k $6.2m | New |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 165.7k $5.5m | Added +11.2k |
| MORGAN STANLEY 0.00% of their portfolio | 134.4k $4.5m | Added +23.8k |
| UBS Group AG 0.00% of their portfolio | 89.9k $3.0m | Reduced -27.1k |
| FEDERATED HERMES, INC. 0.00% of their portfolio | 86.8k $2.9m | Reduced -2.5k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 85.3k $3.0m | Added +627 |
| LAZARD ASSET MANAGEMENT LLC 0.00% of their portfolio | 75.4k $2.5m | New |
| DIMENSIONAL FUND ADVISORS LP 0.00% of their portfolio | 75.3k $2.5m | New |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP 0.00% of their portfolio | 74.6k $2.5m | New |
| JACOBS LEVY EQUITY MANAGEMENT, INC 0.01% of their portfolio | 68.2k $2.3m | Added +39.7k |
| HUSSMAN STRATEGIC ADVISORS, INC. 0.49% of their portfolio | 63.0k $2.1m | Reduced -42.0k |
| AMERICAN CENTURY COMPANIES INC 0.00% of their portfolio | 61.0k $2.0m | Reduced -317 |
| Bank of New York Mellon Corp 0.00% of their portfolio | 56.2k $1.9m | Reduced -2.5k |
| XTX Topco Ltd 0.02% of their portfolio | 54.5k $1.8m | Added +17.8k |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 50.6k $1.7m | Reduced -73.5k |
| BARCLAYS PLC 0.00% of their portfolio | 49.8k $1.7m | Added +27.1k |
| Elmind Capital, LP 0.42% of their portfolio | 49.4k $1.7m | New |
| Nuveen, LLC 0.00% of their portfolio | 48.2k $1.6m | Added +19.1k |
| Sofinnova Investments, Inc. 0.08% of their portfolio | 47.5k $1.6m | Unchanged |
| D. E. Shaw & Co., Inc. 0.00% of their portfolio | 46.5k $1.6m | New |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 45.6k $1.5m | New |
| Voleon Capital Management LP 0.03% of their portfolio | 44.4k $1.5m | New |
| HRT FINANCIAL LP 0.00% of their portfolio | 42.0k $1.4m | New |
| RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio | 41.4k $1.4m | Added +3.7k |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 40.2k $1.3m | Added +28.7k |
| Caption Management, LLC 0.04% of their portfolio | 38.0k $1.3m | New |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 35.9k $1.2m | Added +9.9k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 35.3k $1.2m | Added +7.2k |
| Alyeska Investment Group, L.P. 0.00% of their portfolio | 35.0k $1.2m | Unchanged |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 29.9k $718.5k | Added +10.3k |
| Brevan Howard Capital Management LP 0.01% of their portfolio | 29.5k $986.3k | New |
| HighVista Strategies LLC 0.22% of their portfolio | 29.3k $982.5k | New |
| TUDOR INVESTMENT CORP ET AL 0.00% of their portfolio | 29.0k $970.1k | New |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 27.6k $925.5k | Added +1.0k |
| Trexquant Investment LP 0.01% of their portfolio | 25.6k $858.9k | Reduced -9.7k |
| Invesco Ltd. 0.00% of their portfolio | 24.1k $806.9k | Reduced -58.8k |
| Logos Global Management LP 0.03% of their portfolio | 23.5k $788.6k | Unchanged |
| FMR LLC 0.00% of their portfolio | 23.2k $778.3k | Reduced -206 |
| FOX RUN MANAGEMENT, L.L.C. 0.12% of their portfolio | 22.0k $738.1k | New |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 21.9k $732.5k | Added +5.0k |
| Squarepoint Ops LLC 0.00% of their portfolio | 21.2k $710.6k | Added +3.1k |
| STRS OHIO 0.00% of their portfolio | 21.0k $703.3k | Added +3.8k |
| ACADIAN ASSET MANAGEMENT LLC 0.00% of their portfolio | 21.0k $701.0k | Reduced -10.0k |
| FRED ALGER MANAGEMENT, LLC 0.00% of their portfolio | 21.0k $701.9k | New |
| Jump Financial, LLC 0.01% of their portfolio | 20.2k $676.5k | Reduced -32.8k |
| Swiss National Bank 0.00% of their portfolio | 19.8k $663.1k | Reduced -2.3k |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 19.7k $659.2k | Added +9.8k |
| FRANKLIN RESOURCES INC 0.00% of their portfolio | 18.6k $623.1k | New |
| CITIGROUP INC 0.00% of their portfolio | 17.8k $596.4k | Added +8.6k |
| Aquatic Capital Management LLC 0.02% of their portfolio | 17.4k $583.6k | New |
| Engineers Gate Manager LP 0.01% of their portfolio | 17.4k $581.1k | Added +822 |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 16.9k $567.5k | Added +11.6k |
| LOS ANGELES CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 16.6k $555.8k | Added +2.4k |
| State of Wyoming 0.06% of their portfolio | 16.4k $548.5k | New |
| Vanguard Global Advisers, LLC 0.00% of their portfolio | 16.2k $544.1k | Unchanged |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 15.4k $515.6k | Added +22 |
| VIRGINIA RETIREMENT SYSTEMS ET Al 0.00% of their portfolio | 13.3k $445.4k | New |
| Verdad Advisers, LP 0.42% of their portfolio | 13.0k $434.4k | New |
| MetLife Investment Management, LLC 0.00% of their portfolio | 12.9k $431.4k | Reduced -805 |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 12.6k $421.8k | Reduced -104 |
| Man Group plc 0.00% of their portfolio | 11.5k $384.1k | Reduced -389 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio | 10.9k $363.9k | Added +9.7k |
| China Universal Asset Management Co., Ltd. 0.02% of their portfolio | 10.8k $360.8k | Reduced -1.2k |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 10.2k $341.4k | Added +172 |
| Legal & General Group Plc 0.00% of their portfolio | 10.1k $337.0k | Added +4.3k |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ 0.00% of their portfolio | 10.0k $334.3k | Reduced -400 |
| Gotham Asset Management, LLC 0.00% of their portfolio | 9.3k $312.2k | New |
| Virtus Investment Advisers, LLC 0.07% of their portfolio | 9.1k $304.8k | Reduced -1.6k |
| CANADA PENSION PLAN INVESTMENT BOARD 0.00% of their portfolio | 8.9k $298.1k | New |
| NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio | 8.5k $284.7k | Added +2.9k |
| FIRST TRUST ADVISORS LP 0.00% of their portfolio | 7.7k $259.2k | New |