SEC Form 4 · Updated Daily
STX
— SEAGATE TECHNOLOGY HOLDINGS PUBLIC LIMITED COMPANY OwnershipInsider and institutional ownership derived from SEC Form 4 filings. Click any owner to see their holdings across every company they’ve filed on, and how their position has changed over time.
Current Reporting Owners
| Owner | Role | Shares Owned | As Of | Last Activity |
|---|---|---|---|---|
| NEW SAC | Reporting Owner | 25,001,325 | 2006-01-03 | J |
| HUTCHINS GLENN H | Director | 23,061,080 | 2006-08-16 | S |
| ValueAct Capital Master Fund B, L.P. | Director | 19,852,193 | 2021-04-30 | S |
| SAMSUNG ELECTRONICS CO LTD /FI | 10%+ Owner | 12,539,490 | 2013-10-21 | S |
| RAPPAPORT ANDREW | 10%+ Owner | 10,429,196 | 2006-01-03 | J |
| AUGUST CAPITAL III FOUNDERS FUND LP | 10%+ Owner | 10,429,196 | 2006-01-03 | J |
| JOHNSTON JOHN R | 10%+ Owner | 10,429,196 | 2006-01-03 | J |
| AUGUST CAPITAL MANAGEMENT III LLC | 10%+ Owner | 10,429,196 | 2006-01-03 | J |
| AUGUST CAPITAL STRATEGIC PARTNERS III LP | 10%+ Owner | 10,429,196 | 2006-01-03 | J |
| AUGUST CAPITAL III LP | 10%+ Owner | 10,429,196 | 2006-01-03 | J |
| MARQUARDT DAVID F | Director | 1,196,652 | 2009-11-30 | S |
| KRYDER MARK H | Officer | 965,890 | 2007-05-02 | M |
| HUDSON WILLIAM L | Officer | 908,692 | 2007-12-28 | M |
| WATKINS WILLIAM D | Director | 806,999 | 2008-01-31 | J |
| DEXHEIMER BRIAN S | Officer | 508,331 | 2008-09-12 | A |
| CHIRICO JAMES M | Officer | 492,571 | 2007-07-24 | M |
| MOSLEY WILLIAM D | Director · Officer | 372,750.25 | 2026-10-01 | S |
| LUCZO STEPHEN J | Director | 225,941 | 2022-03-04 | S |
| WICKERSHAM DAVID A | Officer | 194,857 | 2008-09-12 | A |
| O MALLEY PATRICK J | Officer | 169,563 | 2015-09-21 | A |
| Romano Gianluca | Officer | 120,740 | 2026-09-14 | M |
| MASSARONI KENNETH M | Officer | 108,433 | 2017-06-12 | S |
| ABBOTT TODD | Officer | 87,000 | 2008-01-31 | J |
| Whitmore Robert W | Officer | 83,364 | 2013-05-30 | M |
| POPE CHARLES C | Officer | 80,200 | 2008-10-27 | S |
| Pimentel Albert A | Officer | 70,996 | 2015-09-21 | A |
| DAVIDSON JAMES | Director | 67,499 | 2007-11-02 | M |
| Teh Ban Seng | Officer | 58,540 | 2026-09-14 | M |
| Nygaard Jeffrey D. | Officer | 58,360 | 2023-02-01 | M |
| GLEMBOCKI JERRY S | Officer | 57,885 | 2008-09-12 | A |
| PETERSON GLEN A | Officer | 57,510 | 2008-09-12 | A |
| RE MARK | Officer | 40,470 | 2017-05-15 | S |
| DEHAAN DOUGLAS J | Officer | 39,111 | 2015-09-21 | A |
| Naik Ravi | Officer | 38,857 | 2023-03-22 | F |
| PARK CHONG SUP | Director | 32,527 | 2018-10-18 | F |
| Morris John Christopher | Officer | 32,047.25 | 2026-09-21 | M |
| CLEMMER RICHARD L | Director | 31,284 | 2026-10-24 | M |
| SCHUELKE KATHERINE | Officer | 29,311 | 2023-12-09 | M |
| THOMPSON JOHN WENDELL | Director | 27,948 | 2010-10-27 | A |
| Chong Kian Fatt | Officer | 25,093 | 2026-09-14 | M |
| MARSHALL LYDIA MICHEAUX | Director | 24,535 | 2014-10-21 | F |
| CHENG MEI WEI | Director | 24,256 | 2018-10-18 | M |
| Onken Kristen M | Director | 23,729 | 2016-10-18 | F |
| MORTON DAVID H JR | Director | 23,346 | 2018-07-25 | A |
| WINGERT MICHAEL J | Officer | 20,008 | 2007-02-23 | M |
| Lerner James J | Officer | 17,858 | 2015-03-11 | S |
| MacPherson Regan J | Officer | 16,702 | 2016-11-16 | S |
| Fochtman Jeffrey D. | Officer | 16,670 | 2022-09-12 | M |
| COLEMAN WILLIAM T III | Director | 16,492 | 2020-10-21 | M |
| Haggart Dylan G. | Director | 16,095 | 2026-10-24 | M |
| BRACE PHILIP G | Director · Officer | 16,069 | 2018-01-11 | S |
| CANNON MICHAEL R | Director | 15,307 | 2026-10-24 | M |
| BRUNER JUDY | Director | 14,961 | 2025-10-19 | M |
| BHATT PRAT | Director | 14,449 | 2026-10-24 | M |
| BRADLEY WILLIAM W | Director | 12,500 | 2009-10-28 | A |
| Tilenius Stephanie | Director | 12,244 | 2026-10-24 | M |
| MURPHY JAMES J | Officer | 10,569 | 2019-12-20 | F |
| ValueAct Holdings II, L.P. | Director | 9,009 | 2022-10-20 | M |
| VA Partners I, LLC | Director | 9,009 | 2022-10-20 | M |
| ValueAct Holdings GP, LLC | Director | 9,009 | 2022-10-20 | M |
| ValueAct Capital Management, LLC | Director | 9,009 | 2022-10-20 | M |
| ValueAct Capital Master Fund, L.P. | Director | 9,009 | 2022-10-20 | M |
| ValueAct Holdings, L.P. | Director | 9,009 | 2022-10-20 | M |
| ValueAct Capital Management, L.P. | Director | 9,009 | 2022-10-20 | M |
| KIERNAN DONALD E | Director | 8,750 | 2008-10-30 | A |
| Hottier-Fayon Geraldine | Officer | 8,634.67 | 2018-09-22 | A |
| Arumugavelu Shankar | Director | 8,206 | 2026-10-24 | M |
| Richarz David K | Officer | 7,944 | 2015-04-24 | M |
| ROGGE KAREN M | Director | 6,680.27 | 2006-03-02 | M |
| BRUGGEWORTH ROBERT A | Director | 6,591 | 2024-10-19 | M |
| BIONDI FRANK | Director | 5,399 | 2017-10-17 | F |
| Conyers Yolanda Lee | Director | 4,931 | 2026-10-24 | M |
| Scolnick Kathryn R. | Officer | 4,768.02 | 2018-09-22 | A |
| ZANDER EDWARD J | Director | 3,803 | 2023-10-23 | M |
| Adams Mark | Director | 3,626 | 2026-10-24 | M |
| Moyo Dambisa F | Director | 3,316 | 2017-10-24 | S |
| JEONG SEH-WOONG | Director | 2,518 | 2014-10-21 | F |
| Anderson David Z | Officer | 2,500 | 2009-10-23 | S |
| Szlosek Thomas A | Director | 1,938.39 | 2026-10-24 | M |
| Geldmacher Jay L | Director | 1,803 | 2026-10-24 | M |
| Lee James CI | Officer | 1,584 | 2026-10-22 | M |
| REYES GREGORIO | Director | 0 | 2015-10-21 | F |
Recent Filings
| Date | Owner | Activity | Shares | Price | Owned After |
|---|---|---|---|---|---|
| 2026-10-24 | Adams Mark | Grant / award (derivative) | 345 | $0.00 | 345 |
| 2026-10-24 | Adams Mark | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | Adams Mark | Tax withholding | 380 | $630.49 | 3,246 |
| 2026-10-24 | Adams Mark | Option exercise | 1,580 | $0.00 | 3,626 |
| 2026-10-24 | Arumugavelu Shankar | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | Arumugavelu Shankar | Tax withholding | 380 | $630.49 | 7,826 |
| 2026-10-24 | Arumugavelu Shankar | Option exercise | 1,580 | $0.00 | 8,206 |
| 2026-10-24 | BHATT PRAT | Grant / award (derivative) | 345 | $0.00 | 345 |
| 2026-10-24 | BHATT PRAT | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | BHATT PRAT | Tax withholding | 380 | $630.49 | 14,069 |
| 2026-10-24 | BHATT PRAT | Option exercise | 1,580 | $0.00 | 14,449 |
| 2026-10-24 | CANNON MICHAEL R | Option exercise (derivative) | 1,868 | $0.00 | 0 |
| 2026-10-24 | CANNON MICHAEL R | Tax withholding | 449 | $630.49 | 14,858 |
| 2026-10-24 | CANNON MICHAEL R | Option exercise | 1,868 | $0.00 | 15,307 |
| 2026-10-24 | CLEMMER RICHARD L | Grant / award (derivative) | 345 | $0.00 | 345 |
| 2026-10-24 | CLEMMER RICHARD L | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | CLEMMER RICHARD L | Tax withholding | 380 | $630.49 | 30,904 |
| 2026-10-24 | CLEMMER RICHARD L | Option exercise | 1,580 | $0.00 | 31,284 |
| 2026-10-24 | Conyers Yolanda Lee | Grant / award (derivative) | 345 | $0.00 | 345 |
| 2026-10-24 | Conyers Yolanda Lee | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | Conyers Yolanda Lee | Tax withholding | 380 | $630.49 | 4,551 |
| 2026-10-24 | Conyers Yolanda Lee | Option exercise | 1,580 | $0.00 | 4,931 |
| 2026-10-24 | Geldmacher Jay L | Grant / award (derivative) | 345 | $0.00 | 345 |
| 2026-10-24 | Geldmacher Jay L | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | Geldmacher Jay L | Tax withholding | 380 | $630.49 | 1,423 |
| 2026-10-24 | Geldmacher Jay L | Option exercise | 1,580 | $0.00 | 1,803 |
| 2026-10-24 | Haggart Dylan G. | Grant / award (derivative) | 345 | $0.00 | 345 |
| 2026-10-24 | Haggart Dylan G. | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | Haggart Dylan G. | Tax withholding | 380 | $630.49 | 15,715 |
| 2026-10-24 | Haggart Dylan G. | Option exercise | 1,580 | $0.00 | 16,095 |
| 2026-10-24 | Szlosek Thomas A | Grant / award (derivative) | 345 | $0.00 | 345 |
| 2026-10-24 | Szlosek Thomas A | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | Szlosek Thomas A | Tax withholding | 380 | $630.49 | 1,558.39 |
| 2026-10-24 | Szlosek Thomas A | Option exercise | 1,580 | $0.00 | 1,938.39 |
| 2026-10-24 | Tilenius Stephanie | Grant / award (derivative) | 345 | $0.00 | 345 |
| 2026-10-24 | Tilenius Stephanie | Option exercise (derivative) | 1,580 | $0.00 | 0 |
| 2026-10-24 | Tilenius Stephanie | Tax withholding | 380 | $630.49 | 11,864 |
| 2026-10-24 | Tilenius Stephanie | Option exercise | 1,580 | $0.00 | 12,244 |
| 2026-10-23 | Lee James CI | Open-market sale | 547.25 | $642.14 | 1,036.75 |
| 2026-10-22 | Lee James CI | Option exercise (derivative) | 1,237 | $0.00 | 8,665 |
Source: SEC EDGAR Form 4 filings. For informational purposes only — not investment advice.