Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 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 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Wang David H 2. Issuer Name and Ticker or Trading Symbol ACM Research, Inc. [ACMR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director __X__ 10% Owner __X__ Officer (give title below) _____ Other (specify below) See Remarks (Last) (First) (Middle) C/O ACM RESEARCH, INC., 42307 OSGOOD ROAD, SUITE I 3. Date of Earliest Transaction (Month/Day/Year) 10/27/2025 (Street) FREMONT, CA 94539 4. If Amendment, Date 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 (City) (State) (Zip) 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 100,002 I By Jing Chen, wife of David H. Wang Class A Common Stock 45,837 I By Sophia Wang, daughter of David H. Wang Class A Common Stock 180,000 I By David Hui Wang and Jing Chen Family Irrevocable Trust for Wang Children Class A Common Stock 620,001 I By Wang-Chen Family Living Trust

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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 Underlying Securities (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 of Derivative Security: 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

$7.36

10/27/2025

A

545,400

(1)(2)

03/19/2030

Class A Common Stock

545,400

$ 0

545,400

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Wang David H C/O ACM RESEARCH, INC. 42307 OSGOOD ROAD, SUITE I FREMONT, CA 94539	X	X	See Remarks

Signatures

/s/ Mark McKechnie, Attorney-in-Fact for David H. Wang		10/29/2025
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	On March 20, 2020, the reporting person was granted options to purchase an aggregate of 1,636,197 shares of the Issuer's Class A common stock, based on the satisfaction of certain performance criteria. In general, one-third of the shares subject to the options vest and become exercisable upon an increase in the Issuer's market capitalization (calculated as described in footnote 2) of $1 billion, $2 billion and $3 billion, respectively, from the market capitalization of $553,383,586 on the date of grant. 545,400 shares vested and became exercisable on October 27, 2025, which was the first trading day as of which the Issuer's market capitalization equaled or exceeded $2,553,383,586. The remaining shares will vest and become exercise upon the first trading days, if any, on which the Issuer's market capitalization equals or exceeds $3,553,383,586.
(2)	For purposes of the options, the market capitalization as of a specified trading day is calculated by multiplying (a) the average of the daily volume-weighted average price per share of the Issuer's Class A common stock for each of the trading days occurring during the thirty calendar day period ending on that specified trading day by (b) the total number of issued and outstanding shares of the Issuer's Class A and Class B common stock as of 11:59 p.m. (Eastern time) on such specified trading day.
Remarks: Chief Executive Officer, President and Director

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