X0306 4 2021-05-21 0 0001113232 AXCELIS TECHNOLOGIES INC ACLS 0001420601 Lawson Douglas A. C/O AXCELIS TECHNOLOGIES, INC. 108 CHERRY HILL DRIVE BEVERLY MA 01915 0 1 0 0 EVP, Corporate Mktg & Strategy Common Stock 2021-05-21 4 S 0 5829 40.28 D 47852 D The price reported in Column 4 is a weighted-average price. These shares were sold in multiple transactions at prices ranging from $40.20 to $40.78, inclusive. The reporting person undertakes to provide to Axcelis Technologies, Inc., any security holder of Axcelis Technologies, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price. Of the shares held as of May 21, 2021, 34,613 were issuable on vesting of restricted stock units granted to the executive under the 2012 Equity Incentive Plan and are subject to forfeiture. Lynnette C. Fallon, as attorney in fact for Douglas A. Lawson 2021-05-21