Officer at ACM Research (NASDAQ: ACMR) nets 30,000-share sale

Rhea-AI Filing Summary

ACM Research, Inc. officer Lisa Feng exercised stock options and sold shares of Class A Common Stock. On March 5 and 6, 2026, she exercised options for a total of 30,000 shares of Class A Common Stock at an exercise price of $4.55 per share through derivative conversions.

Over those two days she sold a total of 30,000 shares of Class A Common Stock in open-market transactions at weighted average prices ranging from $45.51 to $50.54, under a Rule 10b5‑1 trading plan adopted on December 2, 2025. Following these transactions, she directly holds 50,001 shares of Class A Common Stock.

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^*

Feng Lisa

(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)
03/05/2026

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	03/05/2026		M		15,000	A	$4.55	65,001	D
Class A Common Stock	03/05/2026		S(1)		8,050	D	$49.81(2)	56,951	D
Class A Common Stock	03/05/2026		S(1)		6,950	D	$50.24(3)	50,001	D
Class A Common Stock	03/06/2026		M		15,000	A	$4.55	65,001	D
Class A Common Stock	03/06/2026		S(1)		14,800	D	$46.07(4)	50,201	D
Class A Common Stock	03/06/2026		S(1)		200	D	$46.58(5)	50,001	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	$4.55	03/05/2026		M			15,000	(6)	11/03/2029	Class A Common Stock	15,000	$0	0	D
Stock Option	$4.55	03/06/2026		M			15,000	(6)	11/03/2029	Class A Common Stock	15,000	$0	0	D

Explanation of Responses:

1. The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 2, 2025.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $49.16 to $50.06, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnote (2), (3), (4) and (5) to this Form 4.

3. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $50.16 to $50.54, inclusive.

4. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $45.51 to $46.48, inclusive.

5. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $46.52 to $46.63, inclusive.

6. The option is fully vested and exercisable.

Remarks:

Chief Financial Officer of ACM Research (Shanghai), Inc., a subsidiary of the Issuer

	/s/ Mark McKechnie, Attorney-in-Fact for Lisa Feng	03/09/2026
	** 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.

FAQ

What insider transactions did Lisa Feng report at ACM Research (ACMR)?

Lisa Feng reported exercising options and selling shares of ACM Research Class A Common Stock. She exercised 30,000 shares via option conversions, then sold 30,000 shares in open‑market transactions over two days, while retaining a direct holding of 50,001 shares.

How many ACM Research (ACMR) shares did Lisa Feng sell and at what prices?

Across March 5 and 6, 2026, Lisa Feng sold a total of 30,000 shares of ACM Research Class A Common Stock. Weighted average sale prices ranged from $45.51 to $50.54, with detailed price ranges disclosed in multiple weighted‑average footnotes.

What stock options did Lisa Feng exercise in this ACM Research (ACMR) Form 4?

Lisa Feng exercised stock options covering 15,000 shares on March 5, 2026, and another 15,000 shares on March 6, 2026. Each exercise converted options into Class A Common Stock at an exercise price of $4.55 per share, from options stated as fully vested and exercisable.

Was Lisa Feng’s ACM Research (ACMR) stock sale under a 10b5-1 plan?

Yes. The filing states the sales were made under a Rule 10b5‑1 trading plan. That plan was adopted on December 2, 2025, allowing pre‑scheduled trading instructions intended to separate trading decisions from day‑to‑day, non‑public information.

How many ACM Research (ACMR) shares does Lisa Feng own after these transactions?

After completing the option exercises and related open‑market sales, Lisa Feng directly holds 50,001 shares of ACM Research Class A Common Stock. This figure reflects her reported direct ownership immediately following the last transaction disclosed in the Form 4.

What is the net effect of Lisa Feng’s ACM Research (ACMR) trades on her holdings?

She exercised options for 30,000 new shares and sold 30,000 shares in total, resulting in no net change from those specific trades. Her directly owned position, as reported after all transactions, stands at 50,001 shares of Class A Common Stock.