Meisner Derek M 4

What Happened

• Derek M. Meisner, Chief Legal Officer & Corporate Secretary of Acumen Pharmaceuticals (ABOS), exercised options to acquire 2,090 shares on 2026-03-06 at an exercise price of $1.85 per share (cost = $3,867) and sold those 2,090 shares the same day in the open market at $3.26 per share (gross proceeds = $6,813). The transaction produced roughly $2,946 in gross proceeds before taxes and fees.
• The Form 4 also reports a related derivative disposition of 2,090 shares at $0.00 associated with the option exercise.

Key Details

• Transaction date: 2026-03-06 (reported on Form 4 filed 2026-03-10).
• Exercise: 2,090 shares @ $1.85 = $3,867 (code M).
• Sale: 2,090 shares @ $3.26 = $6,813 (code S).
• Additional line: derivative disposition of 2,090 shares @ $0.00 (reported in filing).
• Footnotes: F1 — sales were automatic under a Rule 10b5-1 trading plan adopted March 29, 2025. F2 — option vests in 48 equal monthly installments (4-year vesting schedule).
• Shares owned after the transactions: not stated in the information provided in this summary.
• Timeliness: The Form 4 was filed on 2026-03-10 for a 2026-03-06 transaction (the filing appears late relative to the typical two-business-day Form 4 deadline).

Context

• This is an exercise followed by an immediate sale (a cashless-like outcome): the option was exercised and the resulting shares were sold under an existing 10b5-1 plan — a routine way insiders monetize option vesting and avoid ad-hoc timing questions.
• For retail investors: sales under pre-established 10b5-1 plans are generally viewed as planned/liquidation transactions rather than a timely signal of management sentiment. Purchases typically carry more informative weight than routine option exercises followed by sales.