[Form 4] ACM Research, Inc. Insider Trading Activity

Rhea-AI Filing Summary

The reporting person, Cheav Sotheara, exercised a previously issued stock option and immediately sold the acquired shares. On 08/22/2025 Mr. Cheav exercised an option with a $13.89 exercise price to purchase 11,152 shares of ACM Research Class A common stock and sold 11,152 shares that same day at $30 per share pursuant to a Rule 10b5-1 trading plan adopted May 15, 2025. After these transactions the reporting person beneficially owns 100,002 shares of Class A common stock. The Form 4 notes the underlying option covers 66,250 shares, is fully vested and exercisable, and includes a vesting schedule for remaining tranches. The reporting person is identified as Senior Vice President, Manufacturing of ACM Research (Shanghai), Inc., a subsidiary of the issuer.

Insights

Securities Analyst

TL;DR: Insider exercised options and sold shares under a pre-established 10b5-1 plan; change in beneficial ownership is disclosed.

The filing discloses a routine Section 16 transaction: exercise of an option at $13.89 for 11,152 shares followed by an immediate sale of the same number of shares at $30 under a Rule 10b5-1 plan adopted May 15, 2025. The filing reports 100,002 shares beneficially owned after the transactions and identifies the reporting persons role within a subsidiary. This is a transparent disclosure of insider liquidity rather than a corporate operational event.

Corporate Governance Expert

TL;DR: Proper Form 4 disclosure of option exercise and 10b5-1 plan sale; documentation of vesting and beneficial ownership provided.

The Form 4 provides required detail: transaction codes, prices, quantities, and an explanation that the sale was effected pursuant to a 10b5-1 plan. It also describes the options vesting schedule and states the option is fully vested and exercisable. Signatory is an attorney-in-fact, indicating authorized filing. From a governance perspective the filing meets disclosure expectations for insider transactions.

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

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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).

X

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^*

Cheav Sotheara

(Last) (First) (Middle)

C/O ACM RESEARCH, INC.

42307 OSGOOD ROAD, SUITE I

(Street)

FREMONT CA 94539

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
ACM Research, Inc. [ ACMR ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
08/22/2025

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
Class A Common Stock	08/22/2025		M(1)		11,152	A	$13.89	111,154	D
Class A Common Stock	08/22/2025		S(2)		11,152	D	$30	100,002	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
Stock Option	$13.89	08/22/2025		M(1)			11,152	(3)	08/09/2033	Class A Common Stock	11,152	$0	66,250	D

Explanation of Responses:

1. On August 22, 2025, the reporting person exercised a previously issued stock option to purchase 11,152 shares of Class A Common Stock of the Issuer.

2. The sale reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on May 15, 2025.

3. The option will vest and become exercisable as to 7,500 shares on May 15, 2026 and the remaining 22,500 shares will vest and become exercisable in equal monthly installments over the following 36 months, subject to continued service through each vesting date. Option is fully vested and exercisable.

Remarks:

Senior Vice President, Manufacturing of ACM Research (Shanghai), Inc., a subsidiary of the Issuer.

	/s/ Mark McKechnie, Attorney-in-Fact for Sotheara Cheav	08/26/2025
	** 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.
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.

FAQ

What did ACMR insider Cheav Sotheara do on 08/22/2025?

He exercised an option to buy 11,152 Class A shares at $13.89 and sold 11,152 shares at $30 on that date.

Were the sales made under a trading plan for ACMR insider Cheav Sotheara?

Yes. The sale was effected pursuant to a Rule 10b5-1 trading plan adopted on May 15, 2025.

How many ACMR shares does the reporting person own after the transactions?

100,002 shares of Class A common stock are beneficially owned following the reported transactions.

What are the terms of the option disclosed in the Form 4?

The option underlying the transaction covers 66,250 shares, is described as fully vested and exercisable, and includes a vesting schedule for remaining tranches.

What is the reporting persons role at ACM Research?

Senior Vice President, Manufacturing of ACM Research (Shanghai), Inc., a subsidiary of the issuer.