ARM HOLDINGS PLC /UK (ARM) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-05-15 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: ARM HOLDINGS PLC /UK (ARM) CIK: 0001973239 --- Reporting Owner --- Name: Grisenthwaite Richard Roy CIK: 0002112445 Role: Officer (Chief Architect) --- Non-Derivative Transactions --- [Transaction #1] Security: Ordinary Shares Date: 2026-05-15 | Code: A (Grant or award) Shares: +5,217 Shares Owned After: 5,543 | Ownership: D (Direct) Footnotes: [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] Represents performance-based restricted stock units granted on May 1, 2025, which vested on May 15, 2026, following certification of the satisfaction of certain performance conditions by the Remuneration Committee (the "Remuneration Committee") of the Board of Directors of the Company. [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [Transaction #2] Security: Ordinary Shares Date: 2026-05-15 | Code: M (Exercise of derivative) Shares: +2,046 Shares Owned After: 7,589 | Ownership: D (Direct) Footnotes: [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. [F4] This RSU award was granted on May 1, 2025. 30% of the award vested on May 15, 2026. 30% of the award will vest on May 15, 2027, and the remaining 40% will vest on May 15, 2028, subject to continued service to the Company. [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [Transaction #3] Security: Ordinary Shares Date: 2026-05-15 | Code: M (Exercise of derivative) Shares: +14,595 Shares Owned After: 22,184 | Ownership: D (Direct) Footnotes: [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. [F4] This RSU award was granted on May 1, 2025. 30% of the award vested on May 15, 2026. 30% of the award will vest on May 15, 2027, and the remaining 40% will vest on May 15, 2028, subject to continued service to the Company. [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [Transaction #4] Security: Ordinary Shares Date: 2026-05-15 | Code: A (Grant or award) Shares: +4,158 Shares Owned After: 26,342 | Ownership: D (Direct) Footnotes: [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. [F5] Represents performance-based RSUs granted on May 13, 2024, which vested on May 15, 2026, following certification of the satisfaction of certain performance conditions by the Remuneration Committee. [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [Transaction #5] Security: Ordinary Shares Date: 2026-05-15 | Code: M (Exercise of derivative) Shares: +1,631 Shares Owned After: 27,973 | Ownership: D (Direct) Footnotes: [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. [F6] This RSU award was granted on May 13, 2024, 30% of which vested on each of May 15, 2025 and May 15, 2026. The remaining 40% will vest on May 15, 2027, subject to continued service to the Company. [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [Transaction #6] Security: Ordinary Shares Date: 2026-05-15 | Code: A (Grant or award) Shares: +13,315 Shares Owned After: 41,288 | Ownership: D (Direct) Footnotes: [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. [F7] Represents performance-based RSUs granted on May 23, 2023, which vested on May 15, 2026, following certification of the satisfaction of certain performance conditions by the Remuneration Committee. [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [Transaction #7] Security: Ordinary Shares Date: 2026-05-15 | Code: M (Exercise of derivative) Shares: +4,352 Shares Owned After: 45,640 | Ownership: D (Direct) Footnotes: [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. [F8] This RSU award was granted on May 23, 2023 and vested on May 15, 2026. [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [Transaction #8] Security: Ordinary Shares Date: 2026-05-15 | Code: F (Payment of exercise/tax) Shares: -21,301 | Price: $209.16 Total Value: $4,455,317.16 Shares Owned After: 24,339 | Ownership: D (Direct) Footnotes: [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. [F9] Ordinary Shares withheld to satisfy tax withholding requirements on vesting of RSUs. [Transaction #9] Security: Ordinary Shares Date: 2026-05-18 | Code: S (Open market sale) Shares: -24,339 | Price: $209.15 Total Value: $5,090,501.85 Shares Owned After: 0 | Ownership: D (Direct) Footnotes: [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. [F10] Represents weighted average sales price. The shares were sold at prices ranging from $209.03 to $209.66. The reporting person will provide upon request, to the SEC, the Issuer or security holder of the Issuer, full information regarding the number of shares sold at each separate price --- Derivative Transactions --- [Transaction #1] Security: Restricted Stock Units Date: 2026-05-15 | Code: A (Grant or award) Shares: +6,648 | Price: $0.00 Shares Owned After: 106,282 | Ownership: D (Direct) Footnotes: [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [F11] This RSU award was granted effective May 15, 2026. 30% will vest on each of May 15, 2027, and May 15, 2028, and the remaining 40% will vest on May 15, 2029, subject to continued service to the Company. [F11] This RSU award was granted effective May 15, 2026. 30% will vest on each of May 15, 2027, and May 15, 2028, and the remaining 40% will vest on May 15, 2029, subject to continued service to the Company. [Transaction #2] Security: Restricted Stock Units Date: 2026-05-15 | Code: A (Grant or award) Shares: +34,785 | Price: $0.00 Shares Owned After: 141,067 | Ownership: D (Direct) Footnotes: [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [F12] This RSU award was granted effective May 15, 2026. 50% will vest on each of May 15, 2028 and May 15, 2029, subject to continued service to the Company. [F12] This RSU award was granted effective May 15, 2026. 50% will vest on each of May 15, 2028 and May 15, 2029, subject to continued service to the Company. [Transaction #3] Security: Restricted Stock Units Date: 2026-05-15 | Code: M (Exercise of derivative) Shares: -2,046 | Price: $0.00 Shares Owned After: 139,021 | Ownership: D (Direct) Footnotes: [F3] Each restricted stock unit ("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% of the award vested on May 15, 2026. 30% of the award will vest on May 15, 2027, and the remaining 40% will vest on May 15, 2028, subject to continued service to the Company. [F4] This RSU award was granted on May 1, 2025. 30% of the award vested on May 15, 2026. 30% of the award will vest on May 15, 2027, and the remaining 40% will vest on May 15, 2028, subject to continued service to the Company. [Transaction #4] Security: Restricted Stock Units Date: 2026-05-15 | Code: M (Exercise of derivative) Shares: -14,595 | Price: $0.00 Shares Owned After: 124,426 | Ownership: D (Direct) Footnotes: [F3] Each restricted stock unit ("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% of the award vested on May 15, 2026. 30% of the award will vest on May 15, 2027, and the remaining 40% will vest on May 15, 2028, subject to continued service to the Company. [F4] This RSU award was granted on May 1, 2025. 30% of the award vested on May 15, 2026. 30% of the award will vest on May 15, 2027, and the remaining 40% will vest on May 15, 2028, subject to continued service to the Company. [Transaction #5] Security: Restricted Stock Units Date: 2026-05-15 | Code: M (Exercise of derivative) Shares: -1,631 | Price: $0.00 Shares Owned After: 122,795 | Ownership: D (Direct) Footnotes: [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [F6] This RSU award was granted on May 13, 2024, 30% of which vested on each of May 15, 2025 and May 15, 2026. The remaining 40% will vest on May 15, 2027, subject to continued service to the Company. [F6] This RSU award was granted on May 13, 2024, 30% of which vested on each of May 15, 2025 and May 15, 2026. The remaining 40% will vest on May 15, 2027, subject to continued service to the Company. [Transaction #6] Security: Restricted Stock Units Date: 2026-05-15 | Code: M (Exercise of derivative) Shares: -4,352 | Price: $0.00 Shares Owned After: 118,443 | Ownership: D (Direct) Footnotes: [F3] Each restricted stock unit ("RSU") represents the right to receive, following vesting, 1 Ordinary Share held in the form of an ADS. [F8] This RSU award was granted on May 23, 2023 and vested on May 15, 2026. [F8] This RSU award was granted on May 23, 2023 and vested on May 15, 2026. --- Footnotes (Complete Index) --- 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. F10: Represents weighted average sales price. The shares were sold at prices ranging from $209.03 to $209.66. The reporting person will provide upon request, to the SEC, the Issuer or security holder of the Issuer, full information regarding the number of shares sold at each separate price F11: This RSU award was granted effective May 15, 2026. 30% will vest on each of May 15, 2027, and May 15, 2028, and the remaining 40% will vest on May 15, 2029, subject to continued service to the Company. F12: This RSU award was granted effective May 15, 2026. 50% will vest on each of May 15, 2028 and May 15, 2029, subject to continued service to the Company. F2: Represents performance-based restricted stock units granted on May 1, 2025, which vested on May 15, 2026, following certification of the satisfaction of certain performance conditions by the Remuneration Committee (the "Remuneration Committee") of the Board of Directors of the Company. F3: Each restricted stock unit ("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% of the award vested on May 15, 2026. 30% of the award will vest on May 15, 2027, and the remaining 40% will vest on May 15, 2028, subject to continued service to the Company. F5: Represents performance-based RSUs granted on May 13, 2024, which vested on May 15, 2026, following certification of the satisfaction of certain performance conditions by the Remuneration Committee. F6: This RSU award was granted on May 13, 2024, 30% of which vested on each of May 15, 2025 and May 15, 2026. The remaining 40% will vest on May 15, 2027, subject to continued service to the Company. F7: Represents performance-based RSUs granted on May 23, 2023, which vested on May 15, 2026, following certification of the satisfaction of certain performance conditions by the Remuneration Committee. F8: This RSU award was granted on May 23, 2023 and vested on May 15, 2026. F9: Ordinary Shares withheld to satisfy tax withholding requirements on vesting of RSUs. --- Signature --- /s/ /s/ George Kanelos, as Attorney-in-Fact for Richard Roy Grisenthwaite (2026-05-19)