ACUMEN PHARMACEUTICALS, INC.

Up to 10,833,331 shares of Common Stock

   
 

This prospectus relates to the resale or other disposition from time to time by the selling stockholders identified in this prospectus, including their transferees, pledgees, donees or successors, of up to 10,833,331 shares of our common stock, par value $0.0001 per share (the "Common Stock") that we issued in a private placement completed on March 16, 2026 (the "Private Placement").

The selling stockholders may, from time to time, sell, transfer or otherwise dispose of any or all of their shares of Common Stock or interests in shares of Common Stock on any stock exchange, market or trading facility on which the shares are traded or in private transactions. These dispositions may be at fixed prices, at prevailing market prices at the time of sale, at prices related to the prevailing market price, at varying prices determined at the time of sale, or at negotiated prices. See "Plan of Distribution" which begins on page 13. We do not know when or in what amount the selling stockholders may dispose of or offer for sale the shares covered by this prospectus.

We are not offering any shares of Common Stock under this prospectus. We will not receive any of the proceeds from the sale of Common Stock by the selling stockholders. All expenses of registration incurred in connection with this offering are being borne by us. The selling stockholders will bear all discounts and commissions, if any, and expenses incurred by them for brokerage, accounting, tax or legal services or any other expenses incurred in their sale of shares of Common Stock.

Our Common Stock is listed on the Nasdaq Global Select Market under the symbol "ABOS." On March 25, 2026, the last reported sale price of our Common Stock was $2.63 per share.