Russell Low - 18 May 2026 Form 4 Insider Report for AXCELIS TECHNOLOGIES INC (ACLS)

Reporting relationship: PRESIDENT AND CEO, Director
Issuer ticker: ACLS
Reported as of: 18 May 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 20 May 2026, 17:05:07 UTC
Prior SEC filing: 19 May 2026
Source filing: View source filing
Reporting owner signature: /s/ Eileen J. Evans, Attorney-in-Fact

Key filing fact

Russell Low filed Form 4 for AXCELIS TECHNOLOGIES INC (ACLS) on 20 May 2026.

Key facts

This page summarizes Russell Low's Form 4 filing for AXCELIS TECHNOLOGIES INC (ACLS).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 20 May 2026, 17:05.

Change

Previous filing in this sequence was filed on 19 May 2026.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001689237 Primary reporting owner

Low Russell

Relationship: PRESIDENT AND CEO, Director
Address: C/O AXCELIS TECHNOLOGIES, INC., 108 CHERRY HILL DRIVE, BEVERLY
Signature: /s/ Eileen J. Evans, Attorney-in-Fact
Signature date: 20 May 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ACLS transaction

Common Stock

Tax liability

Transaction value
Shares: -711
Change %: -0.46%
Price: $146.24^*
Shares after: 154,900
Date: 18 May 2026
Ownership: Direct
Footnotes: F1, F2, F3

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 3 footnotes

Footnote F1

This forfeiture of shares for tax withholding purposes relates to the vesting on May 16, 2026 of service vesting restricted stock units granted to the executive in May 2022. 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 restricted stock units.

Footnote F2

Represents the closing price of the common stock on the date of the tax withholding.

Footnote F3

Of the shares held after this vesting event on May 16, 2026, 106,691 were issuable on vesting of restricted stock units granted to the reporting person under the 2012 Equity Incentive Plan and are subject to forfeiture.