Posner Brian S (CIK 1372455) reported 10 SEC Form 4 insider transactions across 2 companies over the past 18 months (most recent 2026-06-09). Recent activity: Buy DYN (2,000 shares), Buy DYN (2,500 shares), Buy DYN (2,500 shares), Sell ACGL (2,000 shares), Buy ACGL (2,071 shares). Source: SEC Form 4.
| Date | Company | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-06-09 | Dyne Therapeutics, Inc. (DYN) | Director | Buy | 2,000 | $33,880 |
| 2026-06-05 | Dyne Therapeutics, Inc. (DYN) | Director | Buy | 2,500 | $43,700 |
| 2026-05-22 | Dyne Therapeutics, Inc. (DYN) | Director | Buy | 2,500 | $42,800 |
| 2026-05-12 | ARCH CAPITAL GROUP LTD. (ACGL) | Director | Sell | 2,000 | $0 |
| 2026-05-07 | ARCH CAPITAL GROUP LTD. (ACGL) | Director | Buy | 2,071 | $0 |
| 2026-03-13 | Dyne Therapeutics, Inc. (DYN) | Director | Buy | 2,000 | $38,700 |
| 2026-03-12 | ARCH CAPITAL GROUP LTD. (ACGL) | Director | Sell | 3,000 | $0 |
| 2026-03-10 | Dyne Therapeutics, Inc. (DYN) | Director | Buy | 3,000 | $45,180 |
| 2025-08-04 | ARCH CAPITAL GROUP LTD. (ACGL) | Director | Buy | 1,000 | $0 |
| 2025-05-09 | ARCH CAPITAL GROUP LTD. (ACGL) | Director | Buy | 1,564 | $0 |
Source: SEC Form 4 filings · as of 2026-06-09