Axcelis (NASDAQ: ACLS) EVP sells 1,166 shares, retains 27,627

Rhea-AI Filing Summary

Axcelis Technologies executive Christopher Tatnall reported an open-market sale of company stock. On May 20, 2026, the EVP Global Customer Operations sold 1,166 shares of Axcelis common stock at $149.75 per share.

After this transaction, he directly held 27,627 shares. According to the footnote, 20,871 of these shares are issuable upon vesting of restricted stock units granted under the 2012 Equity Incentive Plan and remain subject to forfeiture.

Insider Trade Summary

Net Seller: 1,166 shares ($174,609)

Net Sell 1 txn

Insider Tatnall Christopher

Role EVP Global Customer Operations

Sold 1,166 shs ($175K)

Type	Security	Shares	Price	Value
Sale	Common Stock	1,166	$149.75	$175K

Holdings After Transaction: Common Stock — 27,627 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares sold: 1,166 shares Sale price: $149.75 per share Shares held after transaction: 27,627 shares +1 more

4 metrics

Shares sold 1,166 shares Open-market sale on May 20, 2026

Sale price $149.75 per share Open-market sale of common stock

Shares held after transaction 27,627 shares Direct ownership following May 20, 2026 sale

RSU-related shares 20,871 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

"20,871 shares were issuable on vesting of restricted stock units"

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

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

subject to forfeiture financial

"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^*

Tatnall Christopher

(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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/20/2026

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	05/20/2026		S		1,166	D	$149.75	27,627(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 20, 2026, 20,871 shares 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	05/21/2026
	** 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 Christopher Tatnall?

Axcelis reported that EVP Global Customer Operations Christopher Tatnall sold 1,166 shares of common stock in an open-market transaction on May 20, 2026, at $149.75 per share. This Form 4 filing details his sale and updated share ownership position.

How many Axcelis (ACLS) shares did Christopher Tatnall sell and at what price?

Christopher Tatnall sold 1,166 shares of Axcelis common stock at $149.75 per share on May 20, 2026. The transaction was classified as an open-market sale of non-derivative common stock under SEC Form 4 reporting requirements.

How many Axcelis (ACLS) shares does Christopher Tatnall hold after this Form 4 sale?

Following the May 20, 2026 sale, Christopher Tatnall directly holds 27,627 Axcelis common shares. The filing notes that 20,871 of these shares are tied to restricted stock units that will be issued upon vesting and are still subject to forfeiture conditions.

What does the Axcelis (ACLS) Form 4 say about Tatnall’s restricted stock units?

The Form 4 states that, after the May 20, 2026 sale, 20,871 of Christopher Tatnall’s reported shares are issuable upon vesting of restricted stock units under the 2012 Equity Incentive Plan. These restricted stock units remain subject to forfeiture until vesting conditions are satisfied.

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

The transaction was reported as an open-market sale of common stock. The Form 4 lists transaction code “S” and describes it as a sale in an open market or private transaction, confirming it was a straightforward disposition rather than an option exercise or tax-withholding event.