Form 4 Filing for Christopher Tatnall

This filing details a transaction by Christopher Tatnall, EVP Global Customer Operations at AXCELIS TECHNOLOGIES INC. On April 20, 2026, Mr. Tatnall forfeited 907 shares of common stock, valued at $131.02 per share, for tax withholding purposes related to the vesting of restricted stock units granted in April 2022. This transaction reduced his post-transaction holdings to 23,044 shares. The forfeiture is a standard procedure to cover tax obligations arising from the vesting of equity awards. The filing also notes that 16,463 of the remaining shares are subject to forfeiture related to performance-based restricted stock units granted in 2025.