Septerna, Inc. (SEPN) Ownership
SEPN ownership summary
as of October 18, 2026- Institutions
- 99.1% of shares outstanding
- Insiders
- 2.94% of shares outstanding
- Shares outstanding
- 46.7M
- Float
- 26.4M shares available to trade
- Short interest
- 12.68% 3.1M shares short
- Days to cover
- 9.18 short interest up 7.0% vs prior month
- Institutions 99.09%
- Insiders 2.94%
SEPN top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | RA Capital Management, LLC | 14.99% | 7.0M | $254.3M | — | June 30, 2026 |
| 2 | TRV GP V, LLC | 13.32% | 6.2M | $225.9M | — | June 30, 2026 |
| 3 | Driehaus Capital Management LLC | 9.50% | 4.4M | $161.1M | +37,486 (+0.9%) | June 30, 2026 |
| 4 | TRV GP VI, LLC | 9.02% | 4.2M | $153.1M | — | June 30, 2026 |
| 5 | Samsara BioCapital, LLC | 6.75% | 3.1M | $114.5M | — | June 30, 2026 |
| 6 | The Goldman Sachs Group Inc | 6.56% | 3.1M | $111.3M | +156,339 (+5.4%) | June 30, 2026 |
| 7 | BlackRock Inc | 4.14% | 1.9M | $70.2M | +109,914 (+6.0%) | June 30, 2026 |
| 8 | Siren, L.L.C. | 4.07% | 1.9M | $69.1M | −100,000 (−5.0%) | June 30, 2026 |
| 9 | venBio Select Advisor LLC | 2.87% | 1.3M | $48.6M | — | June 30, 2026 |
| 10 | Jupiter Topco LLC | 2.80% | 1.3M | $47.5M | +1.3M (0.0%) | June 30, 2026 |
| 11 | Vanguard Capital Management, LLC | 2.62% | 1.2M | $44.4M | +24,711 (+2.1%) | June 30, 2026 |
| 12 | PRIMECAP Management Company | 2.50% | 1.2M | $42.4M | +118,548 (+11.3%) | June 30, 2026 |
| 13 | First Light Asset Management, LLC | 2.06% | 963K | $35.0M | +230,400 (+31.4%) | June 30, 2026 |
| 14 | ADAR1 Capital Management LLC | 2.02% | 941K | $34.2M | −149,071 (−13.7%) | June 30, 2026 |
| 15 | HHG PLC | 1.91% | 891K | $32.4M | +890,754 (0.0%) | March 31, 2026 |
| 16 | Geode Capital Management, LLC | 1.46% | 679K | $24.7M | +34,017 (+5.3%) | June 30, 2026 |
| 17 | State Street Corp | 1.40% | 653K | $23.7M | +21,183 (+3.4%) | June 30, 2026 |
| 18 | Loomis, Sayles & Company LP | 1.34% | 625K | $22.7M | +624,752 (0.0%) | June 30, 2026 |
| 19 | Casdin Capital, LLC | 1.19% | 553K | $20.1M | — | June 30, 2026 |
| 20 | Catalio Capital Management, LP | 1.15% | 536K | $19.5M | +241,792 (+82.1%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 12 holders added 3.8M shares and 2 cut 249K.
SEPN top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 1.99% | 928K | $33.7M | — | August 31, 2026 |
| 2 | PRIMECAP Odyssey Aggressive Growth | 1.79% | 835K | $30.4M | +85,598 (+11.4%) | June 30, 2026 |
| 3 | iShares Russell 2000 ETF | 1.23% | 575K | $20.9M | −6,592 (−1.1%) | September 30, 2026 |
| 4 | Driehaus Small Cap Growth Institutional | 0.96% | 448K | $16.3M | +30,636 (+7.3%) | July 31, 2026 |
| 5 | Heptagon Driehaus US Micro Cap Eq C$ Acc | 0.85% | 396K | $14.4M | — | August 31, 2026 |
| 6 | Heptagon Driehaus US Sm Cp Eq C USD Acc | 0.81% | 377K | $13.7M | +17,728 (+4.9%) | August 31, 2026 |
| 7 | Loomis Sayles Small Cap Growth Instl | 0.78% | 365K | $13.3M | −59,616 (−14.1%) | August 31, 2026 |
| 8 | State Street® SPDR® S&P® PhrmctlsETF | 0.55% | 257K | $9.3M | −3,188 (−1.2%) | September 30, 2026 |
| 9 | Fidelity Small Cap Index | 0.52% | 242K | $8.8M | +2,651 (+1.1%) | July 31, 2026 |
| 10 | iShares Biotechnology ETF | 0.49% | 228K | $8.3M | −1,728 (−0.8%) | September 30, 2026 |
| 11 | Driehaus Micro Cap Growth USD | 0.34% | 158K | $5.8M | — | July 31, 2026 |
| 12 | Vanguard US Opportunities Ins USD Acc | 0.30% | 140K | $5.1M | −1,100 (−0.8%) | June 30, 2026 |
| 13 | iShares Russell 2000 Growth ETF | 0.29% | 136K | $5.0M | −173 (−0.1%) | September 30, 2026 |
| 14 | Vanguard Russell 2000 ETF | 0.27% | 127K | $4.6M | +3,137 (+2.5%) | August 31, 2026 |
| 15 | Schwab US Small-Cap ETF™ | 0.27% | 127K | $4.6M | +81 (+0.1%) | September 30, 2026 |
| 16 | Fidelity Extended Market Index | 0.24% | 112K | $4.1M | −2,383 (−2.1%) | August 31, 2026 |
| 17 | Column Small Cap Select | 0.23% | 109K | $4.0M | −2,182 (−2.0%) | June 30, 2026 |
| 18 | North Square Dynamic Small Cap I | 0.23% | 108K | $3.9M | +107,931 (0.0%) | June 30, 2026 |
| 19 | JNL Multi-Manager Small Cap Growth A | 0.22% | 102K | $3.7M | +11,487 (+12.7%) | June 30, 2026 |
| 20 | Hussman Strategic Market Cycle Fund | 0.21% | 100K | $3.6M | +100,000 (0.0%) | March 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
SEPN insider transactions
latest 4| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-04-15 | Elizabeth Bhatt | Sell | $24.34 | 4,000 | $97,360 |
| 2026-03-02 | Samira Shaikhly | Sell | $28.10 | 70,453 | $2.0M |
| 2026-02-18 | Elizabeth Bhatt | Sell | $28.97 | 4,000 | $115,880 |
| 2025-11-10 | Daniel D Long | Sell | $18.06 | 3,501 | $63,228 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
SEPN shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns SEPN
Institutional investors own 99.1% of Septerna's shares and insiders 2.94%. The largest holder is RA Capital Management, LLC with 14.99% of the shares (7.0M), as of June 30, 2026. Among the top 20 institutions, 12 added shares and 2 reduced their stake in the latest filings. Short interest is 12.68% of the float, or 9.18 days of average trading volume. The share count rose 160.6% since 2023.
Related: SEPN analyst forecast, SEPN key metrics. See the SEPN stock overview for the latest quote and news.
SEPN ownership FAQ
Who owns the most Septerna stock?
The largest shareholders of Septerna are RA Capital Management, LLC (14.99%), TRV GP V, LLC (13.32%), Driehaus Capital Management LLC (9.50%), TRV GP VI, LLC (9.02%), Samsara BioCapital, LLC (6.75%).
What percentage of Septerna is owned by institutions?
Institutions hold 99.1% of Septerna's shares outstanding; insiders hold 2.94%.
Which funds own Septerna?
The largest fund holders of Septerna are Vanguard MStar Total Stk Mkt Idx Invest (1.99%), PRIMECAP Odyssey Aggressive Growth (1.79%), iShares Russell 2000 ETF (1.23%), Driehaus Small Cap Growth Institutional (0.96%), Heptagon Driehaus US Micro Cap Eq C$ Acc (0.85%).
What is Septerna's short interest?
3.1M shares of Septerna were sold short, 12.68% of the float; at the average daily volume it would take 9.18 days to cover.
Are insiders buying or selling Septerna?
Of the latest 4 reported insider transactions in Septerna (since November 10, 2025), 0 were purchases and 4 were sales.
How many shares of Septerna are outstanding?
Septerna has 46.7M shares outstanding, of which 26.4M are in the public float.