William D. Mosley - Dec 1, 2025 Form 4 Insider Report for Seagate Technology Holdings plc (STX)

Signature
/s/ Louis J. Thorson, Attorney-in-Fact for William D. Mosley
Stock symbol
STX
Transactions as of
Dec 1, 2025
Transactions value $
-$5,420,577
Form type
4
Date filed
12/2/2025, 05:32 PM
Previous filing
Nov 5, 2025

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
MOSLEY WILLIAM D CEO, Director SEAGATE TECHNOLOGY HOLDINGS PLC, 47488 KATO ROAD, FREMONT /s/ Louis J. Thorson, Attorney-in-Fact for William D. Mosley 2025-12-02 0001388390

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction STX Ordinary Shares Sale -$292K -1.09K -0.23% $267.27 465K Dec 1, 2025 Direct F1, F2
transaction STX Ordinary Shares Sale -$109K -407 -0.09% $268.58 464K Dec 1, 2025 Direct F3
transaction STX Ordinary Shares Sale -$175K -650 -0.14% $269.43 464K Dec 1, 2025 Direct F4
transaction STX Ordinary Shares Sale -$1.44M -5.34K -1.15% $270.29 458K Dec 1, 2025 Direct F5
transaction STX Ordinary Shares Sale -$1.55M -5.72K -1.25% $271.19 452K Dec 1, 2025 Direct F6
transaction STX Ordinary Shares Sale -$1.6M -5.89K -1.3% $272.24 447K Dec 1, 2025 Direct F7
transaction STX Ordinary Shares Sale -$218K -800 -0.18% $273.04 446K Dec 1, 2025 Direct F8
transaction STX Ordinary Shares Sale -$27.5K -100 -0.02% $274.89 446K Dec 1, 2025 Direct
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

Transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).

Explanation of Responses:

Id Content
F1 All transactions reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on February 20, 2025.
F2 These Ordinary Shares were sold in multiple trades at prices ranging from $266.72 to $267.68. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.
F3 These Ordinary Shares were sold in multiple trades at prices ranging from $267.76 to $268.73. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.
F4 These Ordinary Shares were sold in multiple trades at prices ranging from $268.78 to $269.71. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.
F5 These Ordinary Shares were sold in multiple trades at prices ranging from $269.78 to $270.74. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.
F6 These Ordinary Shares were sold in multiple trades at prices ranging from $270.78 to $271.76. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.
F7 These Ordinary Shares were sold in multiple trades at prices ranging from $271.78 to $272.74. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.
F8 These Ordinary Shares were sold in multiple trades at prices ranging from $272.81 to $273.35. The price reported above reflects the weighted average sale price. The Reporting Person hereby undertakes to provide upon request to the SEC staff, the Issuer, or a security holder of the Issuer, full information regarding the number of shares and prices at which the transaction was effected.