Barton Russell 4

What Happened
Barton Russell, COO of Acumen Pharmaceuticals (ABOS), sold a total of 2,777 shares in two open-market transactions on Jan 21–22, 2026 for a combined proceeds of about $5,031. The trades were sales (S) executed at roughly $1.81 and $1.84 per share (2,315 shares @ $1.81 = $4,181; 462 shares @ $1.84 = $850). These sales were reported on a Form 4 filed Jan 23, 2026.

Key Details

• Transaction dates and prices: 2026-01-21 — 2,315 shares @ $1.81 ($4,181); 2026-01-22 — 462 shares @ $1.84 ($850).
• Total shares sold: 2,777; total proceeds ≈ $5,031.
• Shares owned after the transaction: Not disclosed in the supplied filing. See the filed Form 4 for the exact post-transaction holdings.
• Footnotes: F1 — sales were automatic "sell to cover" transactions to satisfy tax withholding on vested restricted stock units, executed under a Rule 10b5-1 trading plan adopted Aug 30, 2024. F2 — reported price is a weighted average; individual sale prices ranged from $1.76 to $1.87 and are available on request to the SEC, the issuer, or security holders.
• Timeliness: Form 4 was filed on Jan 23, 2026 for trades on Jan 21–22, 2026 — appears timely (no late filing flag).

Context
These were routine sell-to-cover transactions tied to RSU vesting and a pre-established 10b5-1 plan, not open-market purchases. Such sales are commonly used solely to pay taxes on vested awards and do not by themselves indicate the insider’s view of the company’s prospects.