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 ($192.7k this quarter). Holder counts are more reliable. Shares outstanding: 44.9m as of 2026-03-02, 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 ≈ $24.03. Options: 2 managers hold calls ($1.8m notional), 0 hold puts (—).
Trends to Q1 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 |
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 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q2 2025 | $439.7k | $12.6m | 28.61 |
| Q3 2025 | $1.7m | $14.0m | 8.22 |
| Q4 2025 | $2.3m | $5.0m | 2.18 |
| Q1 2026 | $1.8m | $0 | 0.00 |
Biggest buyers
| JANUS HENDERSON GROUP PLC | New | +890.8k |
| PRIMECAP MANAGEMENT CO/CA/ | Added | +502.7k |
| Balyasny Asset Management L.P. | Added | +233.1k |
| Kalehua Capital Management LLC | Added | +194.5k |
| GOLDMAN SACHS GROUP INC | Added | +191.3k |
| First Light Asset Management, LLC | Added | +112.0k |
| HUSSMAN STRATEGIC ADVISORS, INC. | New | +105.0k |
| Checkpoint Capital L.P. | New | +100.3k |
| STATE STREET CORP | Added | +91.4k |
| GEODE CAPITAL MANAGEMENT, LLC | Added | +72.4k |
Biggest sellers
| PERCEPTIVE ADVISORS LLC | Sold out | -433.2k |
| Driehaus Capital Management LLC | Reduced | -413.9k |
| Woodline Partners LP | Sold out | -385.3k |
| BVF INC/IL | Reduced | -367.5k |
| MARSHALL WACE, LLP | Reduced | -187.1k |
| Soleus Capital Management, L.P. | Reduced | -108.4k |
| Venrock Adviser, LLC | Reduced | -104.8k |
| Invesco Ltd. | Reduced | -79.1k |
| HighVista Strategies LLC | Sold out | -78.7k |
| CITADEL ADVISORS LLC | Sold out | -75.9k |
Biggest calls
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $1.8m73.0k shares |
| SIMPLEX TRADING, LLC | Added | $57.7k2.4k shares |
Biggest puts
| None |
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 in Q1 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 |
|---|---|---|---|---|---|
| Q2 2024 | 0 | — | 0 | — | — |
| Q3 2024 | 0 | — | 0 | — | — |
| 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 |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2026-03-02 | Shaikhly Samira Chief People Officer | Sold plan | $2.0m70.5k shares |
| 2026-02-18 | Bhatt Elizabeth President and COO | Sold plan | $115.9k4.0k 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, Q1 2026
| Manager | Shares | Change |
|---|---|---|
| RA CAPITAL MANAGEMENT, L.P. 1.78% of their portfolio | 7.0m $168.1m | Unchanged |
| TRV GP V, LLC 37.25% of their portfolio | 6.2m $149.4m | Unchanged |
| Driehaus Capital Management LLC 0.78% of their portfolio | 4.4m $105.6m | Reduced -413.9k |
| TRV GP VI, LLC 74.64% of their portfolio | 4.2m $101.2m | Unchanged |
| SAMSARA BIOCAPITAL, LLC 7.35% of their portfolio | 3.1m $75.7m | Unchanged |
| GOLDMAN SACHS GROUP INC 0.01% of their portfolio | 2.9m $69.8m | Added +191.3k |
| Siren, L.L.C. 1.33% of their portfolio | 2.0m $48.1m | Unchanged |
| BlackRock, Inc. 0.00% of their portfolio | 1.8m $43.8m | Added +20.8k |
| BVF INC/IL 1.04% of their portfolio | 1.4m $32.5m | Reduced -367.5k |
| Avoro Capital Advisors LLC 0.32% of their portfolio | 1.3m $32.1m | Unchanged |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 1.2m $28.8m | First filing |
| ADAR1 Capital Management, LLC 1.57% of their portfolio | 1.1m $26.2m | Reduced -67.8k |
| PRIMECAP MANAGEMENT CO/CA/ 0.02% of their portfolio | 1.0m $25.2m | Added +502.7k |
| JANUS HENDERSON GROUP PLC 0.01% of their portfolio | 890.8k $21.3m | New |
| First Light Asset Management, LLC 1.58% of their portfolio | 732.9k $17.6m | Added +112.0k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 645.1k $15.5m | Added +72.4k |
| STATE STREET CORP 0.00% of their portfolio | 631.4k $15.2m | Added +91.4k |
| Casdin Capital, LLC 1.01% of their portfolio | 553.3k $13.3m | Unchanged |
| Venrock Adviser, LLC 0.45% of their portfolio | 506.1k $12.2m | Reduced -104.8k |
| Kalehua Capital Management LLC 3.60% of their portfolio | 389.1k $9.3m | Added +194.5k |
| Catalio Capital Management, LP 1.48% of their portfolio | 294.4k $7.1m | Unchanged |
| Soleus Capital Management, L.P. 0.27% of their portfolio | 275.0k $6.6m | Reduced -108.4k |
| Balyasny Asset Management L.P. 0.01% of their portfolio | 236.7k $5.7m | Added +233.1k |
| Universal- Beteiligungs- und Servicegesellschaft mbH 0.01% of their portfolio | 224.0k $5.4m | Added +1.3k |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 195.0k $4.7m | First filing |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 181.6k $4.4m | Reduced -5.7k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 164.5k $4.0m | Added +10.3k |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 154.5k $3.7m | First filing |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 124.1k $3.0m | Added +16.6k |
| UBS Group AG 0.00% of their portfolio | 117.0k $2.8m | Added +48.2k |
| MORGAN STANLEY 0.00% of their portfolio | 110.5k $2.7m | Added +6.5k |
| HUSSMAN STRATEGIC ADVISORS, INC. 0.55% of their portfolio | 105.0k $2.5m | New |
| Checkpoint Capital L.P. 0.86% of their portfolio | 100.3k $2.4m | New |
| FEDERATED HERMES, INC. 0.00% of their portfolio | 89.3k $2.1m | Added +10.4k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 84.7k $2.0m | Added +16.3k |
| Invesco Ltd. 0.00% of their portfolio | 82.9k $2.0m | Reduced -79.1k |
| TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio | 75.4k $1.8m | Reduced -17.4k |
| Longaeva Partners L.P. 0.09% of their portfolio | 74.6k $1.8m | Added +24.7k |
| AMERICAN CENTURY COMPANIES INC 0.00% of their portfolio | 61.3k $1.5m | Added +10.6k |
| Bank of New York Mellon Corp 0.00% of their portfolio | 58.7k $1.4m | Added +3.4k |
| Jump Financial, LLC 0.02% of their portfolio | 53.0k $1.3m | Added +44.6k |
| Sofinnova Investments, Inc. 0.06% of their portfolio | 47.5k $1.1m | New |
| MARSHALL WACE, LLP 0.00% of their portfolio | 39.8k $957.4k | Reduced -187.1k |
| Rangeley Capital, LLC 1.03% of their portfolio | 39.8k $956.4k | Reduced -26.0k |
| RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio | 37.7k $905.9k | New |
| XTX Topco Ltd 0.02% of their portfolio | 36.7k $882.5k | Added +13.4k |
| Trexquant Investment LP 0.01% of their portfolio | 35.3k $848.3k | Reduced -8.7k |
| Alyeska Investment Group, L.P. 0.00% of their portfolio | 35.0k $841.0k | Unchanged |
| ACADIAN ASSET MANAGEMENT LLC 0.00% of their portfolio | 31.0k $741.0k | Added +101 |
| Nuveen, LLC 0.00% of their portfolio | 29.2k $701.1k | Added +3.4k |
| JACOBS LEVY EQUITY MANAGEMENT, INC 0.00% of their portfolio | 28.4k $683.3k | Reduced -32.9k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 28.1k $675.0k | Added +2.6k |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 26.6k $639.3k | Added +185 |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 26.0k $624.1k | Reduced -11.6k |
| Y-Intercept (Hong Kong) Ltd 0.01% of their portfolio | 25.8k $619.3k | New |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.00% of their portfolio | 24.0k $576.7k | New |
| Logos Global Management LP 0.03% of their portfolio | 23.5k $565.9k | Unchanged |
| FMR LLC 0.00% of their portfolio | 23.4k $563.4k | Added +20.1k |
| BARCLAYS PLC 0.00% of their portfolio | 22.7k $545.8k | Reduced -15.4k |
| Swiss National Bank 0.00% of their portfolio | 22.1k $531.1k | New |
| ALGERT GLOBAL LLC 0.01% of their portfolio | 21.0k $505.5k | Reduced -13.9k |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 19.6k $546.4k | Unchanged |
| Squarepoint Ops LLC 0.00% of their portfolio | 18.1k $434.5k | Added +3.2k |
| STRS OHIO 0.00% of their portfolio | 17.2k $413.3k | Added +2.6k |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 16.8k $404.7k | Added +2.0k |
| VARCOV Co. 0.15% of their portfolio | 16.8k $402.6k | Reduced -5.9k |
| Engineers Gate Manager LP 0.00% of their portfolio | 16.5k $397.2k | New |
| Vanguard Global Advisers, LLC 0.00% of their portfolio | 16.2k $390.4k | First filing |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 15.4k $369.5k | Added +7.5k |
| Numerai GP LLC 0.04% of their portfolio | 15.1k $362.4k | Reduced -30.8k |
| LOS ANGELES CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 14.2k $341.6k | Reduced -4.3k |
| MetLife Investment Management, LLC 0.00% of their portfolio | 13.7k $328.9k | Unchanged |
| EntryPoint Capital, LLC 0.09% of their portfolio | 12.8k $307.0k | New |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 12.7k $305.1k | Added +5 |
| Verition Fund Management LLC 0.00% of their portfolio | 12.3k $296.6k | New |
| China Universal Asset Management Co., Ltd. 0.02% of their portfolio | 11.9k $287.1k | Added +1.6k |
| Man Group plc 0.00% of their portfolio | 11.9k $284.9k | New |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 11.5k $276.7k | Reduced -3.8k |
| Seven Fleet Capital Management LP 0.09% of their portfolio | 11.4k $275.0k | Unchanged |
| Virtus Investment Advisers, LLC 0.07% of their portfolio | 10.7k $257.6k | Added +262 |
| MASSACHUSETTS FINANCIAL SERVICES CO /MA/ 0.00% of their portfolio | 10.4k $249.5k | New |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 10.0k $240.8k | Added +87 |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 9.9k $237.2k | Reduced -16.7k |
| CITIGROUP INC 0.00% of their portfolio | 9.2k $221.0k | Reduced -366 |
| WINTON GROUP Ltd 0.01% of their portfolio | 8.8k $212.5k | New |
| VANGUARD ASSET MANAGEMENT, Ltd 0.00% of their portfolio | 7.4k $178.3k | First filing |
| Legal & General Group Plc 0.00% of their portfolio | 5.7k $137.8k | Added +3.8k |
| NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio | 5.6k $134.6k | Unchanged |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 5.4k $128.8k | Reduced -88 |
| Police & Firemen's Retirement System of New Jersey 0.00% of their portfolio | 5.2k $124.4k | Unchanged |
| Vanguard Investments Australia, Ltd. 0.00% of their portfolio | 3.9k $93.6k | First filing |
| PUBLIC EMPLOYEES RETIREMENT SYSTEM OF OHIO 0.00% of their portfolio | 3.4k $81.1k | Reduced -7.2k |
| KLP KAPITALFORVALTNING AS 0.00% of their portfolio | 2.5k $60.1k | New |
| Mirae Asset Global Investments Co., Ltd. 0.00% of their portfolio | 2.3k $56.1k | Added +159 |
| Covestor Ltd 0.04% of their portfolio | 2.3k $54.0k | Added +319 |
| Ameritas Investment Partners, Inc. 0.00% of their portfolio | 1.9k $46.7k | Unchanged |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 0.00% of their portfolio | 1.2k $27.8k | Reduced -159 |
| GAMMA Investing LLC 0.00% of their portfolio | 1.1k $26.7k | Added +194 |
| GF FUND MANAGEMENT CO. LTD. 0.00% of their portfolio | 1.0k $24.2k | Added +128 |
| SIGNATUREFD, LLC 0.00% of their portfolio | 966 $23.2k | Reduced -23 |