Monitor for additional insider buying or a material catalyst (e.g., pipeline update, partnership) that could validate this conviction buy. The gift of shares preceding the purchase may indicate estate planning rather than a bearish signal, but the net insider activity (gifts + buy) is mixed. Given poor historical follow-through on PRTA insider buys, treat this as a modest positive signal until corroborated by fundamental news.
Price Chart
Executive Summary
10% owner William Scully made a $439K open-market purchase of PRTA shares at $8.79, adding to his position after gifting over 963K shares earlier in the same week. The buy is modest relative to the $477M market cap (~0.09%), but as a standalone conviction buy by a major insider, it signals confidence at a depressed price. Historical calibration shows past insider buys on PRTA have been unreliable at T+20 (29% win rate), tempering the signal's strength.
Key Financial Metrics
Key Facts
- 10% owner William Scully purchased 50,000 shares at $8.79 for $439K on 2026-08-20
- Purchase represents ~0.09% of PRTA's $477M market cap
- Scully also gifted 963,553 shares (non-cash) on 2026-08-17 and 2026-08-18
- PRTA has 67% analyst bullish consensus (2 Strong Buy, 6 Buy)
- Past insider buy signals on PRTA have a 29% T+20 win rate with -6.07% avg return
Financial Impact
$439K open-market purchase by 10% owner
Risk Factors
- Insider gifts of 963K shares before the buy could indicate non-trading motives (e.g., estate planning) rather than pure conviction
- Historical insider buy signals on PRTA have underperformed at T+20 (29% win rate, -6.07% avg return)
- Biotech sector risk: PRTA's stock is volatile and dependent on clinical trial outcomes
Market Snapshot
Investment Themes
Documents Analyzed
This report is based on 1 SEC document filed with EDGAR.
| Document | Accession Number |
|---|---|
| INSIDER-BUY Data (Synthetic) | 0001045463-26-000014 |
Filters
| Type | Now | ||||
|---|---|---|---|---|---|
Sep 3, 2026 28d ago | Insider Buy | $9.82 $8.86 | ▼ −9.78% | ▼ −8.57% | $8.44 (−14.05%) |
Aug 21, 2026 6w ago | Insider Buy | $9.45 $9.33 | ▼ −1.27% | ▼ −1.74% | $8.44 (−10.69%) |
Aug 10, 2026 7w ago | Insider Buy | $9.12 $8.88 | ▼ −2.63% | ▼ −2.58% | $8.44 (−7.46%) |
Jul 31, 2026 9w ago | Insider Cluster | $8.12 $8.76 | ▲ +7.88% | ▲ +4.37% | $8.44 (+3.94%) |
Jun 18, 2026 15w ago | Insider Buy | $8.93 $9.27 | ▲ +3.81% | ▲ +5.47% | $8.44 (−5.49%) |
Jun 12, 2026 15w ago | Insider Buy | $8.15 $9.15 | ▲ +12.27% | ▲ +13.65% | $8.44 (+3.56%) |
May 14, 2026 20w ago | 3 | $9.76 $9.83 | ▲ +0.72% | ▼ −0.25% | $8.44 (−13.52%) |
May 7, 2026 21w ago | 8-K | $10.73 $9.86 | ▼ −8.11% | ▼ −9.57% | $8.44 (−21.34%) |
Mar 27, 2026 26w ago | DEFA14A | $9.25 $10.36 | ▲ +12.00% | ▲ +7.70% | $8.44 (−8.76%) |
Mar 3, 2026 30w ago | EFFECT | $9.36 $9.77 | ▲ +4.38% | ▲ +4.86% | $8.44 (−9.83%) |
US Market Status
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