Seagate Technology Holdings plc
US ˙ NasdaqGS ˙ IE00BKVD2N49

SecuritySTX / Seagate Technology Holdings plc
InstitutionMorgan Stanley
Latest Disclosed Ownership4,759,312 shares
Latest Disclosed Value $ 1,864,509,052
Morgan Stanley reports 10.50% decrease in ownership of STX / Seagate Technology Holdings plc

On May 15, 2026 - Morgan Stanley filed a 13F-HR form disclosing ownership of 4,759,312 shares of Seagate Technology Holdings plc (US:STX) valued at $1,864,508,069 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on May 27, 2026 disclosing 5,317,516 shares of Seagate Technology Holdings plc. This represents a change in shares of -10.50% during the quarter. The current value of the position is $4,477,037,205 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,759,312 -558,204 -10.50 1,864,509 27.32 0.1123
2026-05-27 2025-12-31 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 5,317,516 258,151 5.10 1,464,391 22.61 0.0874
2026-02-13 2025-12-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 5,317,516 258,151 1,464,391 0.0874
2026-05-27 2025-09-30 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 5,059,365 -429,113 -7.82 1,194,314 50.77 0.0723
2025-11-14 2025-09-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 5,059,365 -429,113 1,194,314 0.0723
2025-08-15 2025-06-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 5,488,478 1,678 0.03 792,152 69.95 0.0516
2025-05-15 2025-03-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 5,486,800 896,296 19.53 466,104 17.64 0.0333
2025-05-15 2024-12-31 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,590,504 186,574 4.24 396,206 -17.86 0.0278
2025-02-14 2024-12-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,590,504 186,574 396,206 0.0278
2025-05-14 2024-09-30 13F/A-2 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,403,930 -299,769 -6.37 482,363 -0.70 0.0350
2025-02-14 2024-09-30 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,403,930 -299,769 482,363 0.0350
2024-11-14 2024-09-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,403,930 -299,769 482,363 0.0350
2025-05-14 2024-06-30 13F/A-2 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,703,699 689,362 17.17 485,751 30.04 0.0376
2024-10-17 2024-06-30 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,703,699 689,362 485,751 0.0376
2024-08-14 2024-06-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,703,699 689,362 485,751 0.0376
2024-10-17 2024-03-31 13F/A-2 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,014,337 -174,930 -4.18 373,534 4.45 0.0300
2024-08-16 2024-03-31 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,014,337 -174,930 373,534 0.0035
2024-05-15 2024-03-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,014,337 -174,930 373,534 0.0300
2024-08-16 2023-12-31 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,189,267 217,297 5.47 357,638 36.53 0.0315
2024-02-13 2023-12-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,189,267 217,297 357,638 0.0315
2023-11-15 2023-09-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 3,971,970 -288,022 -6.76 261,952 -0.61 0.0266
2023-08-14 2023-06-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,259,992 -116,972 -2.67 263,566 -8.93 0.0260
2023-05-15 2023-03-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,376,964 600,730 15.91 289,405 45.67 0.0310
2023-02-14 2022-12-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 3,776,234 -37,736 -0.99 198,668 -2.14 0.0226
2022-11-14 2022-09-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 3,813,970 -127,950 -3.25 203,017 -27.91 0.0277
2022-10-27 2022-06-30 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 3,941,920 919,123 30.41 281,611 3.63 0.0366
2022-08-15 2022-06-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 3,941,920 919,123 281,611 0.0366
2022-10-27 2022-03-31 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 3,022,797 -594,636 -16.44 271,748 -33.51 0.0367
2022-05-13 2022-03-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 3,022,797 -594,636 271,748 0.0367
2022-02-14 2021-12-31 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 3,617,433 -577,391 -13.76 408,697 18.07 0.0505
2021-11-15 2021-09-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,194,824 169,996 4.22 346,155 -2.19 0.0466
2021-08-23 2021-06-30 13F/A-1 SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,024,828 -48,594 -1.19 353,904 13.20 0.0467
2021-08-16 2021-06-30 13F SEAGATE TECHNOLOGY HLDNGS PL ORD SHS G7997R103 4,024,828 -48,594 353,904 0.0097
2021-05-17 2021-03-31 13F SEAGATE TECHNOLOGY SHS G7945M107 4,073,422 -20 -0.00 312,635 23.47 0.0459
2021-02-16 2020-12-31 13F SEAGATE TECHNOLOGY SHS G7945M107 4,073,442 757,290 22.84 253,205 54.97 0.0391
2020-11-13 2020-09-30 13F SEAGATE TECHNOLOGY SHS G7945M107 3,316,152 194,167 6.22 163,387 8.11 0.0316
2020-08-14 2020-06-30 13F SEAGATE TECHNOLOGY SHS G7945M107 3,121,985 430,036 15.97 151,137 15.05 0.0335
2020-05-26 2020-03-31 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 2,691,949 179,638 7.15 131,367 -12.12 0.0357
2020-05-15 2020-03-31 13F SEAGATE TECHNOLOGY SHS G7945M107 2,691,949 179,638 131,367 10,091.7241
2020-02-14 2019-12-31 13F SEAGATE TECHNOLOGY SHS G7945M107 2,512,311 -117,735 -4.48 149,483 5.66 0.0348
2019-11-14 2019-09-30 13F SEAGATE TECHNOLOGY SHS G7945M107 2,630,046 138,317 5.55 141,471 20.49 0.0375
2019-08-14 2019-06-30 13F SEAGATE TECHNOLOGY SHS G7945M107 2,491,729 717,007 40.40 117,410 38.14 0.0312
2019-05-15 2019-03-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,774,722 217,225 13.95 84,991 41.41 0.0241
2019-02-14 2018-12-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,557,497 -882,276 -36.16 60,104 -47.97 0.0180
2019-04-23 2018-09-30 13F/A-2 SEAGATE TECHNOLOGY SHS G7945M107 2,439,773 -252,109 -9.37 115,523 -24.00 0.0289
2018-11-20 2018-09-30 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 2,439,773 0 115,523 0.0289
2018-11-14 2018-09-30 13F SEAGATE TECHNOLOGY SHS G7945M107 2,439,773 -252,109 115,523
2019-04-23 2018-06-30 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 2,691,882 1,204,618 81.00 152,011 74.66 0.0411
2018-08-14 2018-06-30 13F SEAGATE TECHNOLOGY SHS G7945M107 2,691,882 1,204,618 152,011
2019-04-23 2018-03-31 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 1,487,264 45,963 3.19 87,033 44.32 0.0242
2018-05-14 2018-03-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,487,264 45,963 87,033
2019-04-23 2017-12-31 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 1,441,301 -35,482 -2.40 60,305 23.11 0.0165
2018-02-14 2017-12-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,441,301 -35,482 60,305
2017-11-14 2017-09-30 13F SEAGATE TECHNOLOGY SHS G7945M107 1,476,783 29,760 2.06 48,985 -12.64 0.0147
2017-08-11 2017-06-30 13F SEAGATE TECHNOLOGY SHS G7945M107 1,447,023 -72,204 -4.75 56,072 -19.64 0.0169
2017-05-22 2017-03-31 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 1,519,227 191,324 14.41 69,779 37.67 0.0214
2017-05-12 2017-03-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,519,227 69,779
2017-02-22 2016-12-31 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 1,327,903 328,601 32.88 50,686 31.57 0.0166
2017-02-13 2016-12-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,327,903 50,686
2016-11-10 2016-09-30 13F SEAGATE TECHNOLOGY SHS G7945M107 999,302 1,791 0.18 38,525 58.54 0.0132
2016-08-12 2016-06-30 13F SEAGATE TECHNOLOGY SHS G7945M107 997,511 250,995 33.62 24,300 -5.50 0.0088
2016-05-12 2016-03-31 13F SEAGATE TECHNOLOGY SHS G7945M107 746,516 -111,818 -13.03 25,715 -18.28 0.0099
2016-02-09 2015-12-31 13F SEAGATE TECHNOLOGY SHS G7945M107 858,334 -122,703 -12.51 31,466 -28.40 0.0114
2016-02-08 2015-09-30 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 981,037 -741,045 -43.03 43,948 -46.27 0.0162
2015-11-09 2015-09-30 13F SEAGATE TECHNOLOGY SHS G7945M107 981,037 43,948
2015-08-12 2015-06-30 13F SEAGATE TECHNOLOGY SHS G7945M107 1,722,082 -58,663 -3.29 81,800 -11.71 0.0284
2015-05-14 2015-03-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,780,745 -180,233 -9.19 92,653 -28.95 0.0341
2015-02-13 2014-12-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,960,978 67,335 3.56 130,405 20.25 0.0477
2014-12-16 2014-09-30 13F/A-1 SEAGATE TECHNOLOGY SHS G7945M107 1,893,643 -40,404 -2.09 108,448 -1.32 0.0417
2014-11-14 2014-09-30 13F SEAGATE TECHNOLOGY SHS G7945M107 1,893,643 108,448
2014-08-12 2014-06-30 13F SEAGATE TECHNOLOGY SHS G7945M107 1,934,047 147,326 8.25 109,894 9.52 0.1880
2014-05-13 2014-03-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,786,721 314,448 21.36 100,341 21.36 0.0420
2014-02-13 2013-12-31 13F SEAGATE TECHNOLOGY SHS G7945M107 1,472,273 150,535 11.39 82,681 42.95 0.0352
2013-11-13 2013-09-30 13F SEAGATE TECHNOLOGY COM ST COM G7945M107 1,321,738 -547,611 -29.29 57,839 -30.98 0.0273
2013-08-08 2013-06-30 13F SEAGATE TECHNOLOGY COM ST COM G7945M107 1,869,349 1,869,349 83,803 0.0423
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.