Richard Roy Grisenthwaite - 18 Mar 2026 Form 3 Insider Report for ARM HOLDINGS PLC /UK (ARM)

Role
Chief Architect
Signature
/s/ George Kanelos, as Attorney-in-Fact for Richard Roy Grisenthwaite
Issuer symbol
ARM
Transactions as of
18 Mar 2026
Net transactions value
$0
Form type
3
Filing time
18 Mar 2026, 17:12:46 UTC
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Grisenthwaite Richard Roy Chief Architect C/O ARM HOLDINGS PLC, 110 FULBOURN ROAD, CAMBRIDGE, UNITED KINGDOM /s/ George Kanelos, as Attorney-in-Fact for Richard Roy Grisenthwaite 18 Mar 2026 0002112445

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
holding ARM Ordinary Shares 326 18 Mar 2026 Direct F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
holding ARM Restricted Stock Units 18 Mar 2026 Ordinary Shares 36,005 Direct F1, F2, F3
holding ARM Restricted Stock Units 18 Mar 2026 Ordinary Shares 6,820 Direct F1, F3, F4
holding ARM Restricted Stock Units 18 Mar 2026 Ordinary Shares 48,652 Direct F1, F3, F4
holding ARM Restricted Stock Units 18 Mar 2026 Ordinary Shares 3,805 Direct F1, F3, F5
holding ARM Restricted Stock Units 18 Mar 2026 Ordinary Shares 4,352 Direct F1, F3, F6
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Ordinary shares, nominal value 0.001 GBP per share ("Ordinary Shares"), are held in the form of American Depositary Shares ("ADSs"). Each ADS represents 1 Ordinary Share.
F2 This restricted stock unit ("RSU") award was granted on December 9, 2025. 30% will vest on each of November 15, 2026 and November 15, 2027, and the remaining 40% will vest on November 15, 2028, subject to continued service to Arm Holdings plc (the "Company").
F3 Each RSU represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS.
F4 This RSU award was granted on May 1, 2025. 30% will vest on each of May 15, 2026, and May 15, 2027, and the remaining 40% will vest on May 15, 2028, subject to continued service to the Company.
F5 This RSU award of 5,435 was granted on May 13, 2024, of which 30% already vested on May 15, 2025. 30% will vest on May 15, 2026, and 40% will vest on May 15, 2027, subject to continued service to the Company.
F6 This RSU award was granted on May 23, 2023, and will vest on May 15, 2026, subject to continued service to the Company.

Remarks:

Exhibit 24 - Power of Attorney