SCHEDULE 13G Filed 2026-07-31 Event — SEC 0002100121-26-000871 →

VANGUARD PORTFOLIO MANAGEMENT LLC → ACM Research Inc ACMR

Stake: — Shares: — CUSIP: 00108J109 Class: Common Stock

Item 4 — Purpose of Transaction

Not extracted from this filing — typically because it's an amendment (13D/A) and Item 4 is unchanged from the parent filing. Read the raw SEC filing →

Cross-References

Insider Activity (last 365d)

20 transactions

6 buys · 10 sales · 4 awards/exercises

Issuer Cluster

3 13D/G filings on this issuer

2 other filings besides this one

Filer Track Record

14 filings by this filer

13 other filings in the data moat

Short Interest · settle 2026-08-31

DTC 4.37

3,970,966 shares short · +20.9% vs prior

Institutional Consensus · 2025-12-31

Held by elite portfolio managers

1 holder · $6.17M

Point72 Asset Mgmt

Form 4 Insider Transactions · last 365d

Date	Insider	Role	Type	Shares	Price	Value
2026-08-20	McKechnie Mark	officer	Option exercise	30,199	$19.49	$589K
2026-08-20	McKechnie Mark	officer	Option exercise	25,000	$13.89	$347K
2026-08-20	McKechnie Mark	officer	Sale	13,625	$76.34	$1.04M
2026-08-20	McKechnie Mark	officer	Sale	30,365	$77.45	$2.35M
2026-08-20	McKechnie Mark	officer	Sale	11,209	$77.89	$873K
2026-08-12	Pappis Charles C	director	Award	6,400	$81.26	$520K
2026-08-12	Pappis Charles C	director	Award	728	$96.13	$70K
2026-08-12	Liu Tracy	director	Award	6,400	$81.26	$520K
2026-08-12	Liu Tracy	director	Award	728	$96.13	$70K
2026-08-12	Dun Haiping	director	Award	6,400	$81.26	$520K
2026-08-12	Dun Haiping	director	Award	728	$96.13	$70K
2026-06-05	Cheav Sotheara	officer	Option exercise	5,399	$13.89	$75K
2026-06-05	Cheav Sotheara	officer	Sale	2,384	$81.73	$195K
2026-06-05	Cheav Sotheara	officer	Sale	968	$82.61	$80K
2026-06-05	Cheav Sotheara	officer	Sale	400	$84.01	$34K
2026-06-05	Cheav Sotheara	officer	Sale	1,647	$85.41	$141K
2026-06-04	Cheav Sotheara	officer	Option exercise	13,351	$13.89	$185K
2026-06-04	Cheav Sotheara	officer	Sale	1,300	$84.08	$109K
2026-06-04	Cheav Sotheara	officer	Sale	9,212	$85.11	$784K
2026-06-04	Cheav Sotheara	officer	Sale	2,839	$85.77	$244K

Other 13D/G Filings on ACM Research Inc

Filed	Form	Filer	Stake	Shares
2024-10-08	SC	Shanghai Science & Technology Venture Capital (Group) Co., Ltd.	—	—	view →
2023-07-18	SC	Shanghai Science & Technology Venture Capital (Group) Co., Ltd.	—	—	view →

Other Filings by VANGUARD PORTFOLIO MANAGEMENT LLC

Filed	Form	Issuer	Stake	Shares
2026-09-03	SCHEDULE 13G	BellRing Brands, Inc.	—	—	view →
2026-09-03	SCHEDULE 13G	CAL-MAINE FOODS INC	—	—	view →
2026-09-03	SCHEDULE 13G	Pediatrix Medical Group, Inc.	—	—	view →
2026-09-03	SCHEDULE 13G	ZIONS BANCORPORATION, NATIONAL ASSOCIATION /UT/	—	—	view →
2026-07-31	SCHEDULE 13G	Atmus Filtration Technologies Inc	—	—	view →
2026-07-31	SCHEDULE 13G	Autodesk Inc	—	—	view →
2026-07-31	SCHEDULE 13G	Argan Inc	—	—	view →
2026-07-31	SCHEDULE 13G	Buckle Inc/The	—	—	view →
2026-07-31	SCHEDULE 13G	AGNT Inc	—	—	view →
2026-07-31	SCHEDULE 13G	Bright Horizons Family Solutions Inc	—	—	view →
2026-07-31	SCHEDULE 13G	Ashland Inc	—	—	view →
2026-07-31	SCHEDULE 13G	Alignment Healthcare Inc	—	—	view →
2026-07-31	SCHEDULE 13G	Astrana Health Inc	—	—	view →

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