Axcelis Technologies EVP Robert Mahoney's Tax Withholding Stock Forfeiture

This Form 4 filing reports that Robert John Mahoney, Executive Vice President of Global Operations at Axcelis Technologies Inc., forfeited shares for tax withholding purposes on May 18, 2026. The transaction involved the forfeiture of 312 total shares (182 and 130 shares in two separate transactions) at a price of $146.24 per share, resulting in total proceeds of approximately $45,626. This forfeiture relates to the vesting of restricted stock units granted in May 2022 that vested on May 16, 2026. The shares were withheld to cover tax obligations associated with the vested RSUs. Following these transactions, Mahoney's direct holdings decreased to 15,565 shares, of which 12,578 shares remain subject to forfeiture as unvested restricted stock units. The filing was signed by attorney-in-fact Eileen J. Evans on May 20, 2026.