ARM HOLDINGS PLC /UK

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of November, 2026

Commission File Number 001-41800

110 Fulbourn Road Cambridge CB1 9NJUnited Kingdom

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

Quarterly report for thethree and six months ended September 30, 2026.

Incorporation by Reference

This Report on Form 6-K shall be deemed to be incorporated by reference into the registration statements on Form S-8 of Arm Holdings plc (File Nos. 333-274544, 333-287614, and 333-295884), including any prospectuses forming a part of such registration statements, and to be a part thereof from the date on which this Report on Form 6-K is filed with the U.S. Securities and Exchange Commission (the “SEC”), to the extent not superseded by documents or reports subsequently filed or furnished.

Background and Certain Defined Terms

In this Report, unless otherwise specified, “the Company,” “Arm,” “we,” “our” and “us” refer to Arm Holdings plc and its wholly owned subsidiaries, as the context may require.

The term “Annual Report” refers to Arm’s annual report on Form 20-F for the fiscal year ended March 31, 2026, filed with the SEC on May 26, 2026.