Russell Low - 02 Mar 2026 Form 4 Insider Report for AXCELIS TECHNOLOGIES INC (ACLS)

Signature
/s/ Eileen J. Evans, Attorney-in-Fact
Issuer symbol
ACLS
Transactions as of
02 Mar 2026
Net transactions value
-$452,554
Form type
4
Filing time
03 Mar 2026, 17:05:06 UTC
Previous filing
20 May 2025

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Low Russell PRESIDENT AND CEO, Director C/O AXCELIS TECHNOLOGIES, INC., 108 CHERRY HILL DRIVE, BEVERLY /s/ Eileen J. Evans, Attorney-in-Fact 03 Mar 2026 0001689237

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction ACLS Common Stock Tax liability $452,554 -5,227 -3.8% $86.58 130,928 02 Mar 2026 Direct F1, F2, F3
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 This forfeiture of shares for tax withholding purposes relates to the vesting on February 28, 2026 of performance-based restricted stock units ("2024 PRSUs") granted to the executive in May 2024. Of the 2024 PRSUs granted, 150% were determined to be earned by the executive pursuant to a resolution of the Axcelis Technologies, Inc. Compensation Committee on February 13, 2025, with half of the earned shares vesting on February 28, 2025 and the remaining half of the earned shares vesting on February 28, 2026. The shares issued to the executive on the vesting were reduced by a number of shares having a value equal to the executive's tax withholding obligation with respect to the vested 2024 PRSUs.
F2 Represents the closing price of the Company's common stock on March 2, 2026, the date of the tax withholding.
F3 Of the shares held after the vesting of the remaining 2024 PRSUs, 79,638 were issuable on vesting of restricted stock units granted to the reporting person under the 2012 Equity Incentive Plan and are subject to forfeiture.