Monitor for actual execution of the sale on Form 4 filings. A large institutional insider signaling intent to sell over $35M in stock is a notable overhang. The stock has shown mixed historical reaction to prior filings, but a large sell signal from a key pre-IPO holder warrants caution.
Price Chart
Executive Summary
RA Capital Nexus Fund III, L.P., a major pre-IPO institutional investor in Septerna, filed a Form 144 on August 12, 2026, indicating intent to sell 746,500 shares of common stock. At the filing, the approximate market value of the proposed sale was $35,973,835. This represents a significant partial exit by a large insider affiliate, though the sale may not be executed immediately.
Key Facts
- RA Capital Nexus Fund III, L.P. filed Form 144 to sell 746,500 shares of Septerna common stock.
- Approximate market value of the proposed sale is $35,973,835.
- Shares were acquired in IPO/private rounds on 10/25/2024 and 05/24/2024.
- The filing is an advance notice of intent to sell; the sale may or may not occur.
- RA Capital is a significant pre-IPO investor, and this filing signals a potential partial exit.
Financial Impact
Proposed sale of 746,500 shares valued at approximately $35.97 million, representing roughly 1.6% of Septerna's $2.2B market cap.
Risk Factors
- Insider selling by a major pre-IPO investor may signal reduced conviction or a need for liquidity.
- The proposed sale represents a material overhang of ~1.6% of market cap.
- Execution of the sale could pressure the stock price, especially given the stock's recent volatility and negative average T+20 alpha on prior reports.
Market Snapshot
Investment Themes
Documents Analyzed
This report is based on 3 SEC documents filed with EDGAR.
| Document | Accession Number |
|---|---|
| 144 Filing (Primary) | 0001178937-26-000041 |
| Document: 0001178937-26-000041-index.html | 0001178937-26-000041 |
| Document: 0001178937-26-000041.txt | 0001178937-26-000041 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
Sep 10, 2026 21d ago | Press Release | $38.51 $38.69 | ▲ +0.47% | ▲ +0.69% | $38.27 (−0.62%) |
Sep 3, 2026 28d ago | 3 | $36.75 $39.55 | ▲ +7.62% | ▲ +8.83% | $38.27 (+4.14%) |
Aug 25, 2026 5w ago | 8-K | $41.30 $37.68 | ▼ −8.77% | ▼ −8.23% | $38.27 (−7.34%) |
Aug 14, 2026 6w ago | Insider Cluster | $44.20 $40.52 | ▲ +8.33% | ▲ +7.14% | $38.27 (+13.42%) |
Aug 14, 2026 6w ago | Insider Cluster | $44.20 $40.52 | ▲ +8.33% | ▲ +7.14% | $38.27 (+13.42%) |
Aug 12, 2026 7w ago | 144 | $45.14 $40.79 | ▲ +9.64% | ▲ +7.67% | $38.27 (+15.22%) |
Aug 12, 2026 7w ago | 144 | $45.14 $40.79 | ▲ +9.64% | ▲ +7.67% | $38.27 (+15.22%) |
Aug 10, 2026 7w ago | 8-K | $47.76 $43.80 | ▼ −8.29% | ▼ −7.89% | $38.27 (−19.87%) |
Aug 10, 2026 7w ago | Press Release | $47.76 $43.80 | ▼ −8.29% | ▼ −7.89% | $38.27 (−19.87%) |
Jul 2, 2026 13w ago | Insider Cluster | $34.00 $37.84 | ▲ +11.29% | ▲ +10.36% | $38.27 (+12.56%) |
US Market Status
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