Septerna SEPN Insider Ownership

Updated Oct 10, 2026

Over the trailing 12 months, SEPN insiders sold $76.05 million worth of shares (1.8Mn shares) in open-market trades, with no open-market purchases.

• A count shows 5 insiders selling SEPN stock on the open market over the past 12 months and none buying.
• Ra Capital Management, L.P. (Director and 10% owner) was SEPN's largest open-market seller in the past 12 months, with $63.45 million of sales (1.49Mn shares); the latest was on August 12, 2026.
• The latest open-market trade in SEPN stock by an insider was a sale of 3.33K shares for $126,078 by Daniel D. Long (SVP, Drug Discovery) on September 1, 2026.
• Apart from open-market trades, SEPN insiders acquired 158.61K shares through option exercises and conversions in the past 12 months.
• Per Business Quant, SEPN insiders together hold 15.44Mn shares based on their latest Form 4 filings, or 33.80% of the 45.67Mn shares outstanding; that total is down 5.47% from 16.33Mn shares at the end of Q2 2026 and down 3.88% from 16.06Mn shares at the end of Q3 2025.
• By type of ownership, SEPN insiders hold 74.62% of their shares directly (11.52Mn shares) and 25.38% indirectly (3.92Mn shares).
• Business Quant counts 10 insiders with holdings in Septerna stock, among the officers, directors and 10% owners who have filed a Form 4 in the past two years.
• SEPN's largest insider holders by reported holdings are Third Rock Ventures V, L.P. (10% owner, 9.22Mn shares), Third Rock Ventures VI, L.P. (10% owner, 4.21Mn shares) and Jeffrey Finer (Chief Executive Officer, 826.91K shares).
• The largest insider, Third Rock Ventures V, L.P., holds 59.73% of SEPN's insider total.
• Over the trailing 12 months, 18 insiders reported transactions in SEPN stock across 33 Form 4 filings.
• The insider data for SEPN reflects Form 4 filings through September 10, 2026.