[Form 4] AXCELIS TECHNOLOGIES INC Insider Trading Activity

Rhea-AI Filing Summary

Christopher Tatnall, EVP Global Customer Operations at Axcelis Technologies, reported a transaction dated 09/15/2025 on Form 4 showing a forfeiture of 137 shares of common stock to satisfy tax withholding related to restricted stock units that vested that day. The filing lists a withholding price of $87.3 per share, representing the closing stock price used for the withholding calculation.

After the withholding, the reporting person beneficially owned 24,304 shares. The filing also states that 19,706 of those shares were issuable on vesting of RSUs granted under the 2012 Equity Incentive Plan and remain subject to forfeiture. The form was signed by an attorney-in-fact on behalf of the reporting person on 09/17/2025.

Positive

• Disclosure of tax withholding via share forfeiture is clear and specific, including the withholding price ($87.3).
• Reporting person retains beneficial ownership of 24,304 shares after the withholding.
• Specific identification of 19,706 shares as issuable under the 2012 Equity Incentive Plan provides transparency on outstanding RSU exposure.

Negative

• 137 shares forfeited to satisfy tax withholding, reducing the reporting person's immediate share count.
• 19,706 shares remain subject to forfeiture, indicating that a substantial portion of holdings are still conditional.

Insights

Corporate Governance Expert

TL;DR: Routine tax-withholding share forfeiture following RSU vesting; no change in director status.

The Form 4 discloses a standard administrative forfeiture of 137 shares to cover tax withholding on vested RSUs, using the closing price of $87.3. The report confirms ongoing beneficial ownership of 24,304 shares and that 19,706 shares remain issuable under the 2012 Equity Incentive Plan and subject to forfeiture. This filing is procedural and does not indicate leadership change or an unusual governance event.

Executive Compensation Analyst

TL;DR: Compensation mechanics visible—RSU vesting and tax withholding handled via share forfeiture.

The document details vesting mechanics: RSUs granted in September 2023 vested on September 15, 2025, and the company withheld shares equal to the tax obligation. The use of share withholding at the closing price ($87.3) is a common practice to satisfy tax liabilities. The disclosure that 19,706 shares are still issuable but subject to forfeiture highlights ongoing conditionality in the executive's equity compensation.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

Tatnall Christopher

(Last) (First) (Middle)

C/O AXCELIS TECHNOLOGIES, INC.

108 CHERRY HILL DRIVE

(Street)

BEVERLY MA 01915

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
AXCELIS TECHNOLOGIES INC [ ACLS ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP Global Customer Operations

3. Date of Earliest Transaction (Month/Day/Year)
09/15/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/15/2025		F		137	D(1)	$87.3(2)	24,304(3)	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. This forfeiture of shares for tax withholding purposes relates to the vesting on September 15, 2025 of service vesting restricted stock units granted to the executive in September 2023. 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.

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

3. Of the shares held after this vesting event on September 15, 2025, 19,706 were issuable on vesting of restricted stock units granted to the reporting person under the 2012 Equity Incentive Plan and are subject to forfeiture.

	/s/ Eileen J. Evans, Attorney-in-Fact	09/17/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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FAQ

What transaction did the ACLS Form 4 report on 09/15/2025?

The Form 4 reports a forfeiture of 137 common shares to satisfy tax withholding for RSUs that vested on 09/15/2025.

How many Axcelis (ACLS) shares does the reporting person own after the transaction?

The reporting person beneficially owned 24,304 shares following the reported transaction.

What price was used to calculate the tax withholding on the forfeited shares?

The withholding used the closing price of $87.3 per share on the transaction date.

How many of the post-transaction shares are still issuable and subject to forfeiture?

19,706 shares were identified as issuable on vesting of restricted stock units under the 2012 Equity Incentive Plan and are subject to forfeiture.

Who filed the Form 4 on behalf of the reporting person?

The Form 4 was signed by Eileen J. Evans, Attorney-in-Fact on 09/17/2025.