Key facts
- This page summarizes William D. Mosley's Form 4 filing for Seagate Technology Holdings plc (STX).
- 28 reported transactions and 1 derivative row are listed below.
- Accepted by SEC: 03 Sep 2026, 16:51.
William D. Mosley - 01 Sep 2026 Form 4 Insider Report for Seagate Technology Holdings plc (STX)
- Reporting relationship
- CEO, Director
- Issuer ticker
- STX
- Reported as of
- 01 Sep 2026
- Net transaction value
- -$24,488,282
- SEC form
- 4
- Accepted by SEC
- 03 Sep 2026, 16:51:26 UTC
- Prior SEC filing
- 24 Aug 2026
- Next SEC filing
- 11 Sep 2026
- Source filing
- View source filing
- Reporting owner signature
- /s/ Louis J. Thorson, Attorney-in-Fact for William D. Mosley
Source evidence
Original filing metadata and source links for verification.
5 source fields
Reporting owner
1 detail
Key filing fact
William D. Mosley filed Form 4 for Seagate Technology Holdings plc (STX) on 03 Sep 2026.
Change
- Previous filing in this sequence was filed on 24 Aug 2026.
- Current net transaction value: -$24,488,282.
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
Filed on Form 4
View source filing
Ownership activity is grounded in SEC Form 4 disclosures.
Reporting Owners (1)
CIK 0001388390
Primary reporting owner
MOSLEY WILLIAM D
- Relationship
- CEO, Director
- Address
- SEAGATE TECHNOLOGY HOLDINGS PLC, 47488 KATO ROAD, FREMONT
- Signature
- /s/ Louis J. Thorson, Attorney-in-Fact for William D. Mosley
- Signature date
- 03 Sep 2026
Reported non-derivative transactions
Shares, units, or other non-derivative securities reported in this filing.
STX
transaction
Ordinary Shares
Options Exercise
- Transaction value
- Shares
- +14,000
- Change %
- +4.5%
- Price
- $46.23*
- Shares after
- 325,168
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F1
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $287,245
- Shares
- -357
- Change %
- -0.11%
- Price
- $804.61
- Shares after
- 324,810
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F2
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $128,888
- Shares
- -160
- Change %
- -0.05%
- Price
- $805.55
- Shares after
- 324,650
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F3
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $129,151
- Shares
- -160
- Change %
- -0.05%
- Price
- $807.19
- Shares after
- 324,490
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F4
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $776,275
- Shares
- -960
- Change %
- -0.3%
- Price
- $808.62
- Shares after
- 323,530
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F5
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $939,080
- Shares
- -1,160
- Change %
- -0.36%
- Price
- $809.55
- Shares after
- 322,370
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F6
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $895,916
- Shares
- -1,105
- Change %
- -0.34%
- Price
- $810.78
- Shares after
- 321,266
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F7
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $1,280,906
- Shares
- -1,578
- Change %
- -0.49%
- Price
- $811.73
- Shares after
- 319,688
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F8
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $975,057
- Shares
- -1,200
- Change %
- -0.38%
- Price
- $812.55
- Shares after
- 318,488
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F9
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $1,660,027
- Shares
- -2,040
- Change %
- -0.64%
- Price
- $813.74
- Shares after
- 316,448
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F10
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $2,344,853
- Shares
- -2,878
- Change %
- -0.91%
- Price
- $814.75
- Shares after
- 313,570
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F11
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $3,715,738
- Shares
- -4,555
- Change %
- -1.5%
- Price
- $815.75
- Shares after
- 309,014
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F12
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $3,501,391
- Shares
- -4,287
- Change %
- -1.4%
- Price
- $816.75
- Shares after
- 304,728
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F13
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $1,700,829
- Shares
- -2,080
- Change %
- -0.68%
- Price
- $817.71
- Shares after
- 302,648
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F14
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $851,533
- Shares
- -1,040
- Change %
- -0.34%
- Price
- $818.78
- Shares after
- 301,608
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F15
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $1,082,194
- Shares
- -1,320
- Change %
- -0.44%
- Price
- $819.84
- Shares after
- 300,288
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F16
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $755,222
- Shares
- -920
- Change %
- -0.31%
- Price
- $820.89
- Shares after
- 299,368
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F17
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $394,584
- Shares
- -480
- Change %
- -0.16%
- Price
- $822.05
- Shares after
- 298,888
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F18
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $493,734
- Shares
- -600
- Change %
- -0.2%
- Price
- $822.89
- Shares after
- 298,288
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F19
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $1,021,820
- Shares
- -1,240
- Change %
- -0.42%
- Price
- $824.05
- Shares after
- 297,048
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F20
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $494,961
- Shares
- -600
- Change %
- -0.2%
- Price
- $824.93
- Shares after
- 296,448
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F21
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $479,079
- Shares
- -580
- Change %
- -0.2%
- Price
- $826.00
- Shares after
- 295,868
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F22
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $281,132
- Shares
- -340
- Change %
- -0.11%
- Price
- $826.86
- Shares after
- 295,528
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F23
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $99,348
- Shares
- -120
- Change %
- -0.04%
- Price
- $827.90
- Shares after
- 295,408
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F24
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $66,328
- Shares
- -80
- Change %
- -0.03%
- Price
- $829.10
- Shares after
- 295,328
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F25
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $66,429
- Shares
- -80
- Change %
- -0.03%
- Price
- $830.36
- Shares after
- 295,248
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F26
STX
transaction
Ordinary Shares
Sale
- Transaction value
- $66,564
- Shares
- -80
- Change %
- -0.03%
- Price
- $832.04
- Shares after
- 295,168
- Date
- 01 Sep 2026
- Ownership
- Direct
- Footnotes
- F27
Reported derivative securities
Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.
STX
transaction
Derivative
NQ Options
Options Exercise
- Transaction value
- Shares
- -14,000
- Change %
- -13%
- Price
- $0.000000*
- Shares after
- 97,100
- Date
- 01 Sep 2026
- Ownership
- Direct
- Underlying class
- Ordinary Shares
- Underlying amount
- 14,000
- Exercise price
- $46.23
- Footnotes
- F28
* marks a reported price that did not pass the local price check.
Additional SEC filing notes
Filing notes and footnotes
Rule 10b5-1 trading plan
These transactions were reported as open-market trades under a Rule 10b5-1 plan. The plan lets an insider set trading instructions in advance, which can reduce the risk of trading while in possession of material nonpublic information.
Original filing language: transaction made pursuant to a contract, instruction, or written plan intended to satisfy Rule 10b5-1(c).
Explanation of responses 28 footnotes
Footnote 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 18, 2026.
Footnote F2
These Ordinary Shares were sold in multiple trades at prices ranging from $804.17 to $804.83. 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.
Footnote F3
These Ordinary Shares were sold in multiple trades at prices ranging from $805.21 to $805.76. 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.
Footnote F4
These Ordinary Shares were sold in multiple trades at prices ranging from $806.93 to $807.42. 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.
Footnote F5
These Ordinary Shares were sold in multiple trades at prices ranging from $808.02 to $809.00. 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.
Footnote F6
These Ordinary Shares were sold in multiple trades at prices ranging from $809.05 to $810.01. 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.
Footnote F7
These Ordinary Shares were sold in multiple trades at prices ranging from $810.17 to $811.14. 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.
Footnote F8
These Ordinary Shares were sold in multiple trades at prices ranging from $811.18 to $812.10. 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.
Footnote F9
These Ordinary Shares were sold in multiple trades at prices ranging from $812.19 to $813.04. 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.
Footnote F10
These Ordinary Shares were sold in multiple trades at prices ranging from $813.20 to $814.19. 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.
Footnote F11
These Ordinary Shares were sold in multiple trades at prices ranging from $814.23 to $815.22. 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.
Footnote F12
These Ordinary Shares were sold in multiple trades at prices ranging from $815.28 to $816.27. 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.
Footnote F13
These Ordinary Shares were sold in multiple trades at prices ranging from $816.28 to $817.27. 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.
Footnote F14
These Ordinary Shares were sold in multiple trades at prices ranging from $817.29 to $818.20. 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.
Footnote F15
These Ordinary Shares were sold in multiple trades at prices ranging from $818.29 to $819.18. 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.
Footnote F16
These Ordinary Shares were sold in multiple trades at prices ranging from $819.32 to $820.29. 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.
Footnote F17
These Ordinary Shares were sold in multiple trades at prices ranging from $820.36 to $821.26. 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.
Footnote F18
These Ordinary Shares were sold in multiple trades at prices ranging from $821.44 to $822.37. 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.
Footnote F19
These Ordinary Shares were sold in multiple trades at prices ranging from $822.47 to $823.42. 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.
Footnote F20
These Ordinary Shares were sold in multiple trades at prices ranging from $823.47 to $824.40. 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.
Footnote F21
These Ordinary Shares were sold in multiple trades at prices ranging from $824.47 to $825.44. 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.
Footnote F22
These Ordinary Shares were sold in multiple trades at prices ranging from $825.51 to $826.27. 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.
Footnote F23
These Ordinary Shares were sold in multiple trades at prices ranging from $826.52 to $827.29. 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.
Footnote F24
These Ordinary Shares were sold in multiple trades at prices ranging from $827.76 to $828.17. 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.
Footnote F25
These Ordinary Shares were sold in multiple trades at prices ranging from $829.09 to $829.10. 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.
Footnote F26
These Ordinary Shares were sold in multiple trades at prices ranging from $830.22 to $830.50. 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.
Footnote F27
These Ordinary Shares were sold in multiple trades at prices ranging from $832.02 to $832.07. 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.
Footnote F28
Options granted to the Reporting Person are subject to a four year vesting schedule. One quarter of the option shares vested on September 9, 2021. The remaining option shares vest in equal monthly installments over the 36 months following September 9, 2021.