Charles C. Pappis - 17 Apr 2026 Form 4 Insider Report for ACM Research, Inc. (ACMR)

Reporting relationship: Director
Issuer ticker: ACMR
Reported as of: 17 Apr 2026
Net transaction value: -$260,000
SEC form: 4
Accepted by SEC: 21 Apr 2026, 16:30:08 UTC
Prior SEC filing: 09 Mar 2026
Source filing: View source filing
Reporting owner signature: /s/ Mark McKechnie, Attorney-in-Fact for Charles Pappis

Key filing fact

Charles C. Pappis filed Form 4 for ACM Research, Inc. (ACMR) on 21 Apr 2026.

Key facts

This page summarizes Charles C. Pappis's Form 4 filing for ACM Research, Inc. (ACMR).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 21 Apr 2026, 16:30.

Change

Previous filing in this sequence was filed on 09 Mar 2026.
Current net transaction value: -$260,000.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001475345 Primary reporting owner

Pappis Charles C

Relationship: Director
Address: C/O ACM RESEARCH, INC., 42307 OSGOOD ROAD, SUITE I, FREMONT
Signature: /s/ Mark McKechnie, Attorney-in-Fact for Charles Pappis
Signature date: 21 Apr 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ACMR transaction

Class A Common Stock

Options Exercise

Transaction value
Shares: +5,000
Change %
Price: $29.18^*
Shares after: 5,000
Date: 17 Apr 2026
Ownership: Direct
Footnotes: F1

ACMR transaction

Class A Common Stock

Sale

Transaction value: $260,000
Shares: -5,000
Change %: -100%
Price: $52.00
Shares after: 0
Date: 17 Apr 2026
Ownership: Direct
Footnotes: F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

ACMR transaction Derivative

Stock Option

Options Exercise

Transaction value
Shares: -5,000
Change %: -100%
Price: $0.000000^*
Shares after: 0
Date: 17 Apr 2026
Ownership: Direct
Underlying class: Class A Common Stock
Underlying amount: 5,000
Exercise price: $29.18
Footnotes: F1, F3

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Rule 10b5-1 trading plan

These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.

Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).

Explanation of responses 3 footnotes

Footnote F1

On April 17, 2026, the reporting person exercised a previously issued stock option to purchase 5,000 shares of Class A Common Stock of the Issuer.

Footnote F2

The sale reported on this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 20, 2025.

Footnote F3

The option is fully vested and exercisable.