Axcelis (ACLS) EVP uses 312 shares to cover RSU tax obligation

Rhea-AI Filing Summary

Axcelis Technologies EVP Global Operations Robert John Mahoney reported routine share dispositions tied to equity compensation. A total of 312 shares of common stock were withheld on May 18, 2026 to cover tax obligations arising from the May 16, 2026 vesting of restricted stock units granted in May 2022. The withholding price matched the common stock’s closing price of $146.24 per share. These transactions were tax-withholding events, not open-market purchases or sales.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Mahoney Robert John

Role EVP Global Operations

Type	Security	Shares	Price	Value
Tax Withholding	Common Stock	182	$146.24	$27K
Tax Withholding	Common Stock	130	$146.24	$19K

Holdings After Transaction: Common Stock — 15,695 shares (Direct, null)

Footnotes (1)

1. 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. Represents the closing price of the common stock on the date of the tax withholding. Of the shares held after this vesting event on May 16, 2026, 12,846 were issuable on vesting of restricted stock units granted to the reporting person under the 2012 Equity Incentive Plan and are subject to forfeiture. Of the shares held after this vesting event on May 16, 2026, 12,578 were issuable on vesting of restricted stock units granted to the reporting person under the 2012 Equity Incentive Plan and are subject to forfeiture.

Key Figures

Total shares for tax withholding: 312 shares First withholding tranche: 130 shares Second withholding tranche: 182 shares +1 more

4 metrics

Total shares for tax withholding 312 shares Tax withholding for RSU vesting on May 16, 2026

First withholding tranche 130 shares Common stock delivered to cover tax liability

Second withholding tranche 182 shares Common stock delivered to cover tax liability

Valuation price per share $146.24 per share Closing price on date of tax withholding

Key Terms

restricted stock units, tax withholding, Equity Incentive Plan, closing price

4 terms

restricted stock units financial

"relates to the vesting on May 16, 2026 of service vesting restricted stock units granted"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

tax withholding financial

"forfeiture of shares for tax withholding purposes relates to the vesting"

Tax withholding is the practice of taking a portion of a payment—such as wages, dividends, or sale proceeds—before it reaches the recipient and sending that portion to the tax authority as an advance on the recipient’s eventual tax bill. For investors it matters because withholding reduces immediate cash received and affects after‑tax returns, estimated tax payments, and whether you may owe more or receive a refund when taxes are finally calculated, like having a small automatic savings set aside for your tax bill.

Equity Incentive Plan financial

"granted to the reporting person under the 2012 Equity Incentive Plan"

An equity incentive plan is a program that gives employees, executives or directors the right to receive company stock or options to buy stock as part of their pay. Think of it as offering slices of future company profit to motivate people to boost long‑term performance; for investors it matters because it can align employee goals with shareholder value but also increases the number of shares outstanding, which can dilute existing ownership.

closing price financial

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

Form 4 Insider Transactions: What Each Field Means →

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

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Mahoney Robert John

(Last) (First) (Middle)

108 CHERRY HILL DRIVE

(Street)

BEVERLY MASSACHUSETTS 01915

(City) (State) (Zip)

UNITED STATES

(Country)

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 Operations

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/18/2026

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

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

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

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	05/18/2026		F		182	D(1)	$146.24(2)	15,695(3)	D
Common Stock	05/18/2026		F		130	D(1)	$146.24(2)	15,565(4)	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 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.

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 May 16, 2026, 12,846 were issuable on vesting of restricted stock units granted to the reporting person under the 2012 Equity Incentive Plan and are subject to forfeiture.

4. Of the shares held after this vesting event on May 16, 2026, 12,578 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	05/20/2026
	** 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.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transaction did Axcelis (ACLS) report for EVP Robert Mahoney?

Axcelis reported routine tax-withholding transactions for EVP Global Operations Robert Mahoney. A total of 312 common shares were forfeited to satisfy tax obligations from vesting restricted stock units granted in May 2022, rather than being sold in the open market.

How many Axcelis (ACLS) shares were used for Robert Mahoney’s tax withholding?

Robert Mahoney used 312 shares for tax withholding, split into 130 shares and 182 shares. These shares covered his tax liability on restricted stock units that vested on May 16, 2026, under a prior equity award.

At what price were the Axcelis (ACLS) shares valued for the tax withholding?

The shares were valued at $146.24 per share, which represented the closing price of Axcelis common stock on the tax-withholding date. This price was used to determine how many shares were needed to satisfy the tax obligation.

Was Robert Mahoney’s Axcelis (ACLS) transaction an open-market sale?

No, the transaction was not an open-market sale. The Form 4 shows shares were automatically forfeited to cover tax withholding on vested restricted stock units, a common administrative step in equity compensation rather than a discretionary stock sale.

What triggered the Axcelis (ACLS) tax-withholding share forfeiture for Robert Mahoney?

The forfeiture was triggered by RSU vesting. Service-vesting restricted stock units granted to Robert Mahoney in May 2022 vested on May 16, 2026, creating a tax liability that was settled by delivering 312 shares for withholding.