Axcelis (ACLS) director sells 900 shares, retains 17,695-share stake

Rhea-AI Filing Summary

Axcelis Technologies director Thomas St. Dennis reported an open-market sale of 900 shares of common stock at $155.37 per share on May 22, 2026.

After this transaction he held 17,695 shares, including 1,440 shares issuable upon vesting of restricted stock units that remain subject to forfeiture.

Insider Trade Summary

Net Seller: 900 shares ($139,833)

Net Sell 1 txn

Insider St Dennis Thomas

Role null

Sold 900 shs ($140K)

Type	Security	Shares	Price	Value
Sale	Common Stock	900	$155.37	$140K

Holdings After Transaction: Common Stock — 17,695 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares sold: 900 shares Sale price: $155.37 per share Post-transaction holdings: 17,695 shares +1 more

4 metrics

Shares sold 900 shares Open-market sale on May 22, 2026

Sale price $155.37 per share Price for the 900 shares sold

Post-transaction holdings 17,695 shares Total common stock held after the sale

RSUs included in holdings 1,440 shares Issuable upon vesting of restricted stock units, subject to forfeiture

Key Terms

open-market sale, restricted stock units, 2012 Equity Incentive Plan, subject to forfeiture

4 terms

open-market sale financial

"transaction_action: open-market sale"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

restricted stock units financial

"1,440 were issuable on vesting of restricted stock units granted to the director"

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.

2012 Equity Incentive Plan financial

"restricted stock units granted to the director under the 2012 Equity Incentive Plan"

subject to forfeiture financial

"units granted under the 2012 Equity Incentive Plan and are subject to forfeiture"

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^*

St Dennis Thomas

(Last) (First) (Middle)

C/O AXCELIS TECHNOLOGIES, INC.

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)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/22/2026

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	05/22/2026		S		900	D	$155.37	17,695(1)	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. Of the shares held after this sale on May 22, 2026, 1,440 were issuable on vesting of restricted stock units granted to the director under the 2012 Equity Incentive Plan and are subject to forfeiture.

	/s/ Eileen J. Evans, Attorney-in-Fact	05/26/2026
	** 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) director Thomas St. Dennis report?

Director Thomas St. Dennis reported an open-market sale of 900 shares of Axcelis common stock. The sale occurred on May 22, 2026, and was executed at a price of $155.37 per share, as shown in the Form 4 filing details.

At what price did the Axcelis (ACLS) director sell his shares?

The Axcelis director sold 900 shares at $155.37 per share. This price reflects the execution level for the reported open-market sale on May 22, 2026, according to the Form 4 transaction data provided in the filing.

How many Axcelis (ACLS) shares does the director hold after the sale?

Following the sale, the director held 17,695 shares of Axcelis common stock. This total includes 1,440 shares that are issuable upon vesting of restricted stock units, which are still subject to forfeiture under the company’s equity plan.

What portion of the Axcelis (ACLS) director’s holdings are restricted stock units?

Of the 17,695 shares held after the transaction, 1,440 are issuable on vesting of restricted stock units. These units were granted under the 2012 Equity Incentive Plan and remain subject to forfeiture until vesting conditions are met.

Was the Axcelis (ACLS) insider sale an open-market transaction?

Yes, the Form 4 classifies the transaction as an open-market sale. The sale code “S” and description indicate it was executed in the open market or a private transaction, rather than being related to option exercises, gifts, or tax withholding.