Vanguard discloses 8.3% Research Inc (ACMR) holding in 13G/A

Rhea-AI Filing Summary

The Vanguard Group filed an amended Schedule 13G reporting beneficial ownership of 4,972,103 shares of Research Inc common stock, representing 8.3% of the class as of the event date of 12/31/2025.

Vanguard reports no sole voting or dispositive power, with 408,800 shares subject to shared voting power and all 4,972,103 shares subject to shared dispositive power. Vanguard states the securities are held in the ordinary course of business and not for the purpose of changing or influencing control. The filing also notes an internal realignment effective 01/12/2026, after which certain Vanguard subsidiaries are expected to report beneficial ownership separately while pursuing the same investment strategies.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

ACM Research Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

00108J109

(CUSIP Number)

12/31/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 00108J109

1

Names of Reporting Persons

The Vanguard Group

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 408,800.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 4,972,103.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,972,103.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

8.30 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: On January 12, 2026, The Vanguard Group, Inc. went through an internal realignment. As of that date, The Vanguard Group, Inc. no longer performs portfolio management services or administers proxy voting. In accordance with SEC Release No. 34-39538 (January 12, 1998), The Vanguard Group, Inc. anticipates that certain subsidiaries or business divisions of subsidiaries of The Vanguard Group, Inc., that currently have, or are deemed to have, beneficial ownership with The Vanguard Group, Inc., will report beneficial ownership separately (on a disaggregated basis) from The Vanguard Group, Inc. in reliance on such release. These subsidiaries and/or business divisions pursue the same investment strategies as previously pursued by The Vanguard Group, Inc. prior to the realignment.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: ACM Research Inc
(b)	Address of issuer's principal executive offices: 42307 Osgood Road, Unit 1, Fremont, CA, 94539
Item 2.
(a)	Name of person filing: The Vanguard Group
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd., Malvern, PA 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 00108J109
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 4972103
(b)	Percent of class: 8.3 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 408800
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 4972103
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. The Vanguard Group, Inc.'s clients, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein. No one other person's interest in the securities reported herein is more than 5%.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

The Vanguard Group

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	01/30/2026

FAQ

What ownership stake does The Vanguard Group report in ACMR (Research Inc)?

The Vanguard Group reports beneficial ownership of 4,972,103 shares of Research Inc common stock, representing 8.3% of the class. This stake is disclosed on an amended Schedule 13G based on an event date of 12/31/2025.

How much voting and dispositive power does Vanguard have over ACMR shares?

Vanguard reports no sole voting or dispositive power over Research Inc shares. It has shared voting power over 408,800 shares and shared dispositive power over 4,972,103 shares, indicating decisions are made jointly with other parties for these holdings.

Why did The Vanguard Group amend its Schedule 13G for ACMR?

The amendment reflects updated ownership of 4,972,103 shares (8.3%) and an internal realignment effective January 12, 2026. Following this realignment, certain Vanguard subsidiaries or business divisions are expected to report beneficial ownership separately while continuing the same investment strategies.

Does Vanguard hold ACMR shares to influence control of the company?

Vanguard certifies the securities were acquired and are held in the ordinary course of business, not to change or influence control of the issuer. It also states the holdings are not part of any transaction aimed at affecting control, other than specified proxy nomination activities.

Who ultimately benefits from Vanguard’s ACMR shareholdings?

Vanguard states its clients, including registered investment companies and other managed accounts, have the right to receive dividends and sale proceeds from the securities. It notes that no single other person’s interest in the reported securities exceeds 5% of the class.

When did the ownership level triggering this ACMR filing occur?

The Schedule 13G/A lists 12/31/2025 as the date of the event requiring the filing. That date reflects when the relevant beneficial ownership position in Research Inc common stock reached a level that triggered the amended reporting requirement under beneficial ownership rules.