Haiping Dun - 09 Mar 2026 Form 4 Insider Report for ACM Research, Inc. (ACMR)

Role
Director
Signature
/s/ Mark McKechnie, Attorney-in-Fact for Haiping Dun
Issuer symbol
ACMR
Transactions as of
09 Mar 2026
Net transactions value
-$217,363
Form type
4
Filing time
11 Mar 2026, 16:30:26 UTC
Previous filing
14 Nov 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Dun Haiping Director C/O ACM RESEARCH, INC., 42307 OSGOOD ROAD, SUITE I, FREMONT /s/ Mark McKechnie, Attorney-in-Fact for Haiping Dun 11 Mar 2026 0001721581

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction ACMR Class A Common Stock Options Exercise +5,000 $5.60* 5,000 09 Mar 2026 Direct
transaction ACMR Class A Common Stock Sale $177,817 -4,100 -82% $43.37 900 09 Mar 2026 Direct F1, F2
transaction ACMR Class A Common Stock Sale $39,546 -900 -100% $43.94 0 09 Mar 2026 Direct F1, F3
holding ACMR Class A Common Stock 100,000 09 Mar 2026 Dun Family GST Trust
holding ACMR Class A Common Stock 755,090 09 Mar 2026 Haiping Dun & Chi-Pin H Dun Revocable Trust

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction ACMR Stock Option Options Exercise -5,000 -8.3% $0.000000* 55,000 09 Mar 2026 Class A Common Stock 5,000 $5.60 Direct F4
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

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).

Explanation of Responses:

Id Content
F1 The sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on August 13, 2025.
F2 The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $42.88 to $43.87, 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) and (3) to this Form 4.
F3 The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $43.90 to $44.00, inclusive.
F4 The option is fully vested and exercisable.