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

Rhea-AI Filing Summary

Insider activity at ACM Research (ACMR): Senior Vice President Sotheara Cheav exercised a stock option on 09/18/2025 to buy 10,000 shares of Class A common stock at an exercise price of $13.89 per share and simultaneously sold 10,000 shares at $35.00 per share under a Rule 10b5-1 trading plan adopted May 15, 2025. Following these transactions the reporting person beneficially owns 100,002 shares and holds options covering 56,250 underlying shares, with a portion of those options vesting through May 2026 and monthly thereafter. The Form 4 was signed on 09/19/2025 by an attorney-in-fact.

Positive

• Reporting compliance: The Form 4 discloses exercise, sale, 10b5-1 plan date, and remaining holdings.
• Ongoing ownership: Reporting person continues to beneficially own 100,002 shares and holds options for 56,250 shares.

Negative

• Share disposition: 10,000 shares were sold, reducing immediate shareholdings.
• Potential liquidity move: The sale was executed under a 10b5-1 plan, indicating the transaction may have been pre-arranged rather than opportunistic trading.

Insights

Securities Analyst

TL;DR: Insider exercised options and sold the same number of shares via a pre-established 10b5-1 plan; residual ownership remains meaningful.

The reporting person exercised 10,000 options at $13.89 and sold 10,000 shares at $35.00 on the same date, consistent with a Rule 10b5-1 plan adopted May 15, 2025. Such transactions commonly reflect routine liquidity or tax planning rather than new information about the company's operations. Post-transaction beneficial ownership is 100,002 shares and the reporting person retains options to acquire 56,250 shares, some of which vest through 2026 and thereafter.

Corporate Governance Expert

TL;DR: Disclosure is compliant and includes required vesting and plan details; no material governance concerns evident.

The Form 4 discloses exercise, sale, Rule 10b5-1 adoption date, and remaining derivative holdings, which aligns with standard disclosure practices. The filing notes the reporting person’s officer role and subsidiary employment. There is no indication of accelerated vesting or related-party transactions in the filing text provided.

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).

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)
09/18/2025

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	09/18/2025		M(1)		10,000	A	$13.89	110,002	D
Class A Common Stock	09/18/2025		S(2)		10,000	D	$35	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	09/18/2025		M(1)			10,000	(3)	08/09/2033	Class A Common Stock	10,000	$0	56,250	D

Explanation of Responses:

1. On September 18, 2025, the reporting person exercised a previously issued stock option to purchase 10,000 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	09/19/2025
	** 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 the ACMR insider do on 09/18/2025?

The reporting person exercised 10,000 options at $13.89 per share and sold 10,000 shares at $35.00 per share on 09/18/2025.

How many ACMR shares does the insider own after the transactions?

After the reported transactions the insider beneficially owns 100,002 shares of ACM Research.

Does the filing mention a trading plan for the sale?

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

What derivative holdings does the insider retain?

The insider holds options covering 56,250 underlying shares; portions vest on May 15, 2026 and thereafter in monthly installments.

What is the reporting person’s role at ACMR?

The filing identifies the reporting person as Senior Vice President, Manufacturing of ACM Research (Shanghai), Inc.