SION Sionna Therapeutics, Inc.
Price Chart
Executive Summary
OrbiMed Advisors LLC filed a Form 144 on May 29, 2026, signaling intent to sell 1,082,480 shares of Sionna Therapeutics common stock, valued at approximately $46.3 million. This represents a large-scale sell by a major pre-IPO investor, following a series of recent sales by the same entity totaling over $39 million in April–May 2026.
Actionable Insight
OrbiMed's continued large-scale selling—now $46.3M in a single notice plus $48.9M in recent sales—signals potential overhang and lack of insider conviction. Despite strong analyst sentiment, the persistent insider distribution warrants caution. Monitor for actual execution and any further 144 filings.
Key Facts
- OrbiMed Advisors LLC (via OrbiMed Private Investments VIII, LP) filed Form 144 to sell 1,082,480 shares of SION common stock.
- Estimated aggregate value of proposed sale: approximately $46.3 million.
- Shares were acquired on 02/10/2025 in the IPO for cash.
- OrbiMed has sold 1,082,480 shares in the past 3 months (since 04/14/2026) totaling ~$48.9 million.
- Recent insider selling (30d) totals $26.7M across 6 transactions, all by OrbiMed.
- Market cap is $1.9B; proposed sale represents ~2.4% of market cap.
- Sionna has 88% analyst bullish consensus (6 Strong Buy, 8 Buy).
Financial Impact
Proposed sale of 1,082,480 shares valued at ~$46.3M, representing ~2.4% of SION's $1.9B market cap.
Risk Factors
- Continued insider selling pressure from a major pre-IPO holder.
- Potential negative signal about near-term prospects or valuation.
- Possible further dilution if OrbiMed continues to reduce its position.
Market Snapshot
Documents Analyzed
This report is based on 3 SEC documents filed with EDGAR.
| Document | Accession Number |
|---|---|
| 144 Filing (Primary) | 0000947871-26-000586 |
| Document: 0000947871-26-000586-index.html | 0000947871-26-000586 |
| Document: 0000947871-26-000586.txt | 0000947871-26-000586 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
|
Jun 11, 2026
3d ago
|
Institutional Cluster
| $34.08 awaiting T+5 | awaiting T+5 | — | $35.92 (+5.40%) |
|
May 30, 2026
16d ago
|
Insider Cluster
| $40.90 $35.37 | ▼ −13.52% | ▼ −10.77% | $35.92 (−12.18%) |
|
May 29, 2026
16d ago
|
144
| $40.90 $35.37 | ▲ +13.52% | ▲ +10.77% | $35.92 (+12.18%) |
|
May 12, 2026
4w ago
|
8-K
| $40.94 $39.24 | ▼ −4.15% | ▼ −4.23% | $35.92 (−12.26%) |
|
May 12, 2026
4w ago
|
Press Release
| $40.94 $39.24 | ▼ −4.15% | ▼ −4.23% | $35.92 (−12.26%) |
|
May 7, 2026
5w ago
|
Insider Cluster
| $43.31 $43.12 | ▲ +0.44% | ▲ +1.94% | $35.92 (+17.06%) |
|
Apr 27, 2026
6w ago
|
Press Release
| $39.21 $40.45 | ▲ +3.16% | ▲ +2.76% | $35.92 (−8.39%) |
|
Apr 16, 2026
8w ago
|
Insider Cluster
| $45.24 $38.35 | ▲ +15.23% | ▲ +16.21% | $35.92 (+20.60%) |
|
Apr 15, 2026
8w ago
|
Insider Cluster
| $45.09 $43.20 | ▲ +4.19% | ▲ +5.83% | $35.92 (+20.34%) |
|
Mar 2, 2026
14w ago
|
Press Release
| $33.92 $37.53 | ▲ +10.64% | ▲ +11.85% | $35.92 (+5.90%) |
US Market Status
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