424B5 1 ny20072993x1_424b5.htm 424B5

Filed Pursuant to Rule 424(b)(5)

Registration No. 333-278041

PROSPECTUS SUPPLEMENT

(To Prospectus dated March 18, 2024)

2,884,615 Shares of Class A Common Stock

We are offering to certain institutional and accredited investors (the “Investors”) 2,884,615 shares of Class A common stock, $0.0001 par value per share (the “Class A Common Stock”), of the Company, at the offering price of $52.00 per share, in a registered direct offering pursuant this prospectus supplement and the accompanying prospectus and a securities purchase agreement dated May 12, 2026, by between the Company and the Investors (the “Purchase Agreement”).

Our Class A Common Stock is listed on the Nasdaq Global Market under the symbol “ACMR.” The last reported sale price of our Class A Common Stock on the Nasdaq Global Market on May 11, 2026 was $64.67 per share.

Investing in our Class A Common Stock involves a high degree of risk. You should carefully read and consider this prospectus supplement, the accompanying prospectus, the documents incorporated by reference herein and therein, and the risk factors described in, and incorporated by reference under, “Risk Factors” beginning on page S-4 of this prospectus supplement, and under similar headings in the other documents in the other documents incorporated by reference herein before investing in any securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Delivery of the Class A Common Stock is expected to be made on or about May 15, 2026, subject to customary closing conditions.

The date of this prospectus is May 12, 2026


			Page
ABOUT THIS PROSPECTUS SUPPLEMENT			S-1
PROSPECTUS SUPPLEMENT SUMMARY			S-2
THE OFFERING			S-3
RISK FACTORS			S-4
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			S-7
USE OF PROCEEDS			S-9
DIVIDEND POLICY			S-10
PLAN OF DISTRIBUTION			S-11
LEGAL MATTERS			S-12
EXPERTS			S-12
WHERE YOU CAN FIND MORE INFORMATION			S-13
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE			S-14


			Page
ABOUT THIS PROSPECTUS			1
ABOUT OUR COMPANY			1
RISK FACTORS			2
USE OF PROCEEDS			4
DESCRIPTION OF CAPITAL STOCK			5
DESCRIPTION OF DEBT SECURITIES			9
DESCRIPTION OF OTHER SECURITIES			17
SELLING STOCKHOLDERS			17
PLAN OF DISTRIBUTION			18
LEGAL MATTERS			19
EXPERTS			19
WHERE YOU CAN FIND MORE INFORMATION			20
INCORPORATION BY REFERENCE			21

SEC Form 424B5 filed by ACM Research Inc.