Western Digital Corporation
MX ˙ BMV ˙ US9581021055
SecurityMX:WDC / Western Digital Corporation
InstitutionMorgan Stanley
Latest Disclosed Ownership7,939,106 shares
Latest Disclosed Value $ 2,147,449,787
Morgan Stanley reports 11.24% decrease in ownership of WDC / Western Digital Corporation

On May 15, 2026 - Morgan Stanley filed a 13F-HR form disclosing ownership of 7,939,106 shares of Western Digital Corporation (MX:WDC) valued at $2,147,449,787 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on May 27, 2026 disclosing 8,944,662 shares of Western Digital Corporation. This represents a change in shares of -11.24% during the quarter.

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 WESTERN DIGITAL COM 958102105 7,939,106 -1,005,556 -11.24 2,147,450 39.36 0.1294
2026-05-27 2025-12-31 13F/A-1 WESTERN DIGITAL COM 958102105 8,944,662 542,040 6.45 1,540,897 52.74 0.0920
2026-02-13 2025-12-31 13F WESTERN DIGITAL COM 958102105 8,944,662 542,040 1,540,897 0.0920
2026-05-27 2025-09-30 13F/A-1 WESTERN DIGITAL COM 958102105 8,402,622 576,348 7.36 1,008,819 101.44 0.0611
2025-11-14 2025-09-30 13F WESTERN DIGITAL COM 958102105 8,402,622 576,348 1,008,819 0.0611
2025-08-15 2025-06-30 13F WESTERN DIGITAL COM 958102105 7,826,274 1,298,198 19.89 500,803 89.75 0.0326
2025-05-15 2025-03-31 13F WESTERN DIGITAL COM 958102105 6,528,076 1,638,585 33.51 263,930 -9.48 0.0189
2025-05-15 2024-12-31 13F/A-1 WESTERN DIGITAL COM 958102105 4,889,491 592,447 13.79 291,560 -0.64 0.0204
2025-02-14 2024-12-31 13F WESTERN DIGITAL COM 958102105 4,889,491 592,447 291,560 0.0204
2025-05-14 2024-09-30 13F/A-2 WESTERN DIGITAL COM 958102105 4,297,044 -5,581,008 -56.50 293,445 -60.79 0.0213
2025-02-14 2024-09-30 13F/A-1 WESTERN DIGITAL COM 958102105 4,297,044 -5,581,008 293,445 0.0213
2024-11-14 2024-09-30 13F WESTERN DIGITAL COM 958102105 4,297,044 -5,581,008 293,445 0.0025
2025-05-14 2024-06-30 13F/A-2 WESTERN DIGITAL COM 958102105 9,878,052 5,143,445 108.64 748,460 131.66 0.0579
2024-10-17 2024-06-30 13F/A-1 WESTERN DIGITAL COM 958102105 9,878,052 5,143,445 748,460 0.0579
2024-08-14 2024-06-30 13F WESTERN DIGITAL COM 958102105 9,878,052 5,143,445 748,460 0.0579
2024-10-17 2024-03-31 13F/A-2 WESTERN DIGITAL COM 958102105 4,734,607 -2,093,598 -30.66 323,090 -9.65 0.0259
2024-08-16 2024-03-31 13F/A-1 WESTERN DIGITAL COM 958102105 4,734,607 -2,093,598 323,090 0.0259
2024-05-15 2024-03-31 13F WESTERN DIGITAL COM 958102105 4,734,607 -2,093,598 323,090 0.0259
2024-08-16 2023-12-31 13F/A-1 WESTERN DIGITAL COM 958102105 6,828,205 4,375,525 178.40 357,593 219.52 0.0315
2024-02-13 2023-12-31 13F WESTERN DIGITAL COM 958102105 6,828,205 4,375,525 357,593 0.0315
2023-11-15 2023-09-30 13F WESTERN DIGITAL COM 958102105 2,452,680 16,563 0.68 111,916 21.12 0.0114
2023-08-14 2023-06-30 13F WESTERN DIGITAL COM 958102105 2,436,117 23,544 0.98 92,402 1.67 0.0091
2023-05-15 2023-03-31 13F WESTERN DIGITAL COM 958102105 2,412,573 -1,315,367 -35.28 90,882 -22.73 0.0097
2023-02-14 2022-12-31 13F WESTERN DIGITAL COM 958102105 3,727,940 434,592 13.20 117,617 9.72 0.0134
2022-11-14 2022-09-30 13F WESTERN DIGITAL COM 958102105 3,293,348 -468,268 -12.45 107,199 -36.43 0.0146
2022-10-27 2022-06-30 13F/A-1 WESTERN DIGITAL COM 958102105 3,761,616 2,288,867 155.41 168,633 130.62 0.0219
2022-08-15 2022-06-30 13F WESTERN DIGITAL COM 958102105 3,761,616 2,288,867 168,633 0.0044
2022-10-27 2022-03-31 13F/A-1 WESTERN DIGITAL COM 958102105 1,472,749 -59,627 -3.89 73,122 -26.82 0.0099
2022-05-13 2022-03-31 13F WESTERN DIGITAL COM 958102105 1,472,749 -59,627 73,122 0.0099
2022-02-14 2021-12-31 13F WESTERN DIGITAL COM 958102105 1,532,376 -225,438 -12.82 99,926 0.72 0.0123
2021-11-15 2021-09-30 13F WESTERN DIGITAL COM 958102105 1,757,814 246,060 16.28 99,210 -7.79 0.0134
2021-08-23 2021-06-30 13F/A-1 WESTERN DIGITAL COM 958102105 1,511,754 180,744 13.58 107,593 21.10 0.0142
2021-08-16 2021-06-30 13F WESTERN DIGITAL COM 958102105 1,511,754 180,744 107,593 0.0030
2021-05-17 2021-03-31 13F WESTERN DIGITAL COM 958102105 1,331,010 45,224 3.52 88,846 24.75 0.0131
2021-02-16 2020-12-31 13F WESTERN DIGITAL COM 958102105 1,285,786 -637,113 -33.13 71,220 1.34 0.0110
2020-11-13 2020-09-30 13F WESTERN DIGITAL COM 958102105 1,922,899 276,107 16.77 70,281 -3.34 0.0136
2020-08-14 2020-06-30 13F WESTERN DIGITAL COM 958102105 1,646,792 299,560 22.24 72,706 29.67 0.0161
2020-05-26 2020-03-31 13F/A-1 WESTERN DIGITAL COM 958102105 1,347,232 -21,471 -1.57 56,072 -35.45 0.0152
2020-05-15 2020-03-31 13F WESTERN DIGITAL COM 958102105 1,347,232 -21,471 56,072 4,307.4985
2020-02-14 2019-12-31 13F WESTERN DIGITAL COM 958102105 1,368,703 136,510 11.08 86,871 18.21 0.0202
2019-11-14 2019-09-30 13F WESTERN DIGITAL COM 958102105 1,232,193 -167,180 -11.95 73,489 10.44 0.0195
2019-08-14 2019-06-30 13F WESTERN DIGITAL COM 958102105 1,399,373 265,276 23.39 66,541 22.08 0.0177
2019-05-15 2019-03-31 13F WESTERN DIGITAL COM 958102105 1,134,097 -1,601,672 -58.55 54,506 -46.11 0.0154
2019-02-14 2018-12-31 13F WESTERN DIGITAL COM 958102105 2,735,769 -870,005 -24.13 101,142 -52.08 0.0303
2019-04-23 2018-09-30 13F/A-2 WESTERN DIGITAL COM 958102105 3,605,774 1,545,390 75.00 211,082 32.35 0.0528
2018-11-20 2018-09-30 13F/A-1 WESTERN DIGITAL COM 958102105 3,605,774 0 211,082 0.0528
2018-11-14 2018-09-30 13F WESTERN DIGITAL COM 958102105 3,605,774 1,545,390 211,082
2019-04-23 2018-06-30 13F/A-1 WESTERN DIGITAL COM 958102105 2,060,384 776,556 60.49 159,493 34.64 0.0431
2018-08-14 2018-06-30 13F WESTERN DIGITAL COM 958102105 2,060,384 776,556 159,493
2019-04-23 2018-03-31 13F/A-1 WESTERN DIGITAL COM 958102105 1,283,828 -254,138 -16.52 118,458 -3.15 0.0329
2018-05-14 2018-03-31 13F WESTERN DIGITAL COM 958102105 1,283,828 -254,138 118,458
2019-04-23 2017-12-31 13F/A-1 WESTERN DIGITAL COM 958102105 1,537,966 -313,283 -16.92 122,314 -23.53 0.0335
2018-02-14 2017-12-31 13F WESTERN DIGITAL COM 958102105 1,537,966 -313,283 122,314
2017-11-14 2017-09-30 13F WESTERN DIGITAL COM 958102105 1,851,249 683,085 58.48 159,949 54.54 0.0479
2017-08-11 2017-06-30 13F WESTERN DIGITAL COM 958102105 1,168,164 -83,259 -6.65 103,501 0.21 0.0313
2017-05-22 2017-03-31 13F/A-1 WESTERN DIGITAL COM 958102105 1,251,423 36,333 2.99 103,280 25.09 0.0317
2017-05-12 2017-03-31 13F WESTERN DIGITAL COM 958102105 1,251,423 103,280
2017-02-22 2016-12-31 13F/A-1 WESTERN DIGITAL COM 958102105 1,215,090 25,179 2.12 82,565 18.67 0.0270
2017-02-13 2016-12-31 13F WESTERN DIGITAL COM 958102105 1,215,090 82,565
2016-11-10 2016-09-30 13F WESTERN DIGITAL COM 958102105 1,189,911 -348,474 -22.65 69,573 -4.31 0.0238
2016-08-12 2016-06-30 13F WESTERN DIGITAL COM 958102105 1,538,385 1,216,834 378.43 72,704 378.66 0.0263
2016-05-12 2016-03-31 13F WESTERN DIGITAL COM 958102105 321,551 -486,347 -60.20 15,189 -68.69 0.0058
2016-02-09 2015-12-31 13F WESTERN DIGITAL COM 958102105 807,898 286,711 55.01 48,514 17.18 0.0176
2016-02-08 2015-09-30 13F/A-1 WESTERN DIGITAL COM 958102105 521,187 -516,928 -49.79 41,403 -49.14 0.0153
2015-11-09 2015-09-30 13F WESTERN DIGITAL COM 958102105 521,187 41,403
2015-08-12 2015-06-30 13F WESTERN DIGITAL COM 958102105 1,038,115 24,802 2.45 81,410 -11.72 0.0282
2015-05-14 2015-03-31 13F WESTERN DIGITAL COM 958102105 1,013,313 315,398 45.19 92,221 19.37 0.0340
2015-02-13 2014-12-31 13F WESTERN DIGITAL COM 958102105 697,915 -427,797 -38.00 77,258 -29.48 0.0283
2014-12-16 2014-09-30 13F/A-1 WESTERN DIGITAL COM 958102105 1,125,712 263,915 30.62 109,554 38.45 0.0421
2014-11-14 2014-09-30 13F WESTERN DIGITAL COM 958102105 1,125,712 109,554
2014-05-13 2014-03-31 13F WESTERN DIGITAL COM 958102105 861,797 -260,458 -23.21 79,129 -15.96 0.0331
2014-02-13 2013-12-31 13F WESTERN DIGITAL COM 958102105 1,122,255 -90,626 -7.47 94,160 22.45 0.0401
2013-11-13 2013-09-30 13F WESTERN DIGITAL CORP COM ST COM 958102105 1,212,881 101,177 9.10 76,897 11.40 0.0363
2013-08-08 2013-06-30 13F WESTERN DIGITAL CORP COM ST COM 958102105 1,111,704 1,111,704 69,026 0.0348
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.