Son Masayoshi - 18 Mar 2026 Form 3 Insider Report for ARM HOLDINGS PLC /UK (ARM)

Reporting relationship: Director
Issuer ticker: ARM
Reported as of: 18 Mar 2026
Net transaction value: $0
SEC form: 3
Accepted by SEC: 18 Mar 2026, 16:50:58 UTC
Source filing: View source filing
Reporting owner signature: /s/ George Kanelos, as Attorney-in-Fact for Masayoshi Son

Key filing fact

Son Masayoshi filed Form 3 for ARM HOLDINGS PLC /UK (ARM) on 18 Mar 2026.

Key facts

This page summarizes Son Masayoshi's Form 3 filing for ARM HOLDINGS PLC /UK (ARM).
0 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 18 Mar 2026, 16:50.

Change

No earlier filing in this sequence is available for direct comparison.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Official SEC source

Ownership activity is grounded in SEC Form 3 disclosures.

View source filing

Reporting Owners (1)

CIK 0001065520 Primary reporting owner

MASAYOSHI SON

Relationship: Director
Address: 1-7-1 KAIGAN, MINATO-KU, TOKYO, JAPAN
Signature: /s/ George Kanelos, as Attorney-in-Fact for Masayoshi Son
Signature date: 18 Mar 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ARM holding

Ordinary Shares

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 0
Date: 18 Mar 2026
Ownership: Direct
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote F1

922,733,999 ordinary shares, nominal value 0.001 GBP per share ("Ordinary Shares"), of Arm Holdings plc are held of record by Kronos II LLC ("Kronos II"), an indirect wholly-owned subsidiary of SoftBank Group Corp. ("SoftBank Group"). The Ordinary Shares held by Kronos II may be represented by American Depositary Shares, each representing one Ordinary Share. The reporting person is Representative Director, Corporate Officer, Chairman and CEO of SoftBank Group. The reporting person disclaims beneficial ownership of the Ordinary Shares held by Kronos II.

SEC remarks

Exhibit 24 - Power of Attorney