144 0001388390 XXXXXXXX LIVE 0001137789 SEAGATE TECHNOLOGY HOLDINGS PUBLIC LIMITED COMPANY 001-31560 121 Woodlands Avenue 5 Singapore U0 739009 6560182562 WILLIAM MOSLEY Director Officer Common Morgan Stanley Smith Barney LLC Executive Financial Services

1 New York Plaza 8th Floor New York NY 10004

20000 7835200.00 218073067 04/01/2026 NASDAQ Common 09/10/2015 Restricted Stock Units Issuer N 9862 09/10/2015 N/A Common 09/11/2018 Performance Stock Units Issuer N 10029 09/11/2018 N/A Common 07/31/2018 Employee Stock Purchase Plan Issuer N 109 07/31/2018 Cash N WILLIAM MOSLEY

121 Woodlands Avenue 5 Singapore U0 739009

Common 03/19/2026 24584 10000033.68 10b5-1 Sales for WILLIAM MOSLEY

121 Woodlands Avenue 5 Singapore U0 739009

Common 03/02/2026 20000 7695262.00 10b5-1 Sales for WILLIAM MOSLEY

121 Woodlands Avenue 5 Singapore U0 739009

Common 02/02/2026 20000 8585358.00 10b5-1 Sales for WILLIAM MOSLEY

121 Woodlands Avenue 5 Singapore U0 739009

Common 01/02/2026 20000 5711244.00 The securities to be sold were or will be acquired upon the vesting of performance stock units during the period of 09/11/2018 through 09/22/2018. The securities to be sold were acquired upon the vesting of restricted stock units during the period of 09/10/2015 through 09/12/2015. 04/01/2026 02/20/2025 /s/ William D. Mosley