Western Digital Corporation
MX ˙ BMV ˙ US9581021055
SecurityMX:WDC / Western Digital Corporation
InstitutionRobotti Robert
Latest Disclosed Ownership46,544 shares
Latest Disclosed Value $ 12,589,687
Robotti Robert reports 45.13% decrease in ownership of WDC / Western Digital Corporation

On May 13, 2026 - Robotti Robert filed a 13F-HR form disclosing ownership of 46,544 shares of Western Digital Corporation (MX:WDC) valued at $12,589,687 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on February 18, 2026 disclosing 84,833 shares of Western Digital Corporation. This represents a change in shares of -45.13% 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)
2026-05-13 2026-03-31 13F WESTERN DIGITAL COM 958102105 46,544 -38,289 -45.13 12,590 -13.86 1.9633
2026-02-18 2025-12-31 13F/A-1 WESTERN DIGITAL COM 958102105 84,833 -1,072 -1.25 14,614 41.70 2.6246
2026-02-12 2025-12-31 13F WESTERN DIGITAL COM 958102105 84,833 -1,072 14,614 2.0568
2025-11-12 2025-09-30 13F WESTERN DIGITAL COM 958102105 85,905 -490 -0.57 10,314 86.56 1.7893
2025-08-13 2025-06-30 13F WESTERN DIGITAL COM 958102105 86,395 -135 -0.16 5,528 58.03 0.9291
2025-05-13 2025-03-31 13F WESTERN DIGITAL COM 958102105 86,530 3,000 3.59 3,498 -29.76 0.7010
2025-02-12 2024-12-31 13F WESTERN DIGITAL COM 958102105 83,530 535 0.64 4,981 -12.12 0.8742
2024-11-14 2024-09-30 13F WESTERN DIGITAL COM 958102105 82,995 685 0.83 5,668 -9.12 0.8627
2024-08-14 2024-06-30 13F WESTERN DIGITAL COM 958102105 82,310 -55,520 -40.28 6,237 -33.69 0.9770
2024-05-15 2024-03-31 13F WESTERN DIGITAL COM 958102105 137,830 955 0.70 9,406 31.21 1.2763
2024-02-14 2023-12-31 13F WESTERN DIGITAL COM 958102105 136,875 -1,805 -1.30 7,168 13.29 1.0320
2023-11-14 2023-09-30 13F WESTERN DIGITAL COM 958102105 138,680 -1,848 -1.32 6,328 18.71 0.9294
2023-08-14 2023-06-30 13F WESTERN DIGITAL COM 958102105 140,528 -1,038 -0.73 5,330 -0.04 0.8606
2023-05-12 2023-03-31 13F WESTERN DIGITAL COM 958102105 141,566 795 0.56 5,333 20.06 0.9392
2023-03-03 2022-12-31 13F/A-1 WESTERN DIGITAL COM 958102105 140,771 -785 -0.55 4,441 -3.62 0.8854
2023-02-14 2022-12-31 13F WESTERN DIGITAL COM 958102105 140,771 -785 4,441 0.4208
2022-11-14 2022-09-30 13F WESTERN DIGITAL COM 958102105 141,556 -145 -0.10 4,608 -27.47 1.0949
2022-08-12 2022-06-30 13F WESTERN DIGITAL COM 958102105 141,701 1,055 0.75 6,353 -9.02 1.5540
2022-05-16 2022-03-31 13F WESTERN DIGITAL COM 958102105 140,646 430 0.31 6,983 -23.62 1.4132
2022-02-14 2021-12-31 13F WESTERN DIGITAL COM 958102105 140,216 -2,662 -1.86 9,143 13.38 1.8530
2021-11-15 2021-09-30 13F WESTERN DIGITAL COM 958102105 142,878 -152 -0.11 8,064 -20.78 1.8500
2021-08-16 2021-06-30 13F WESTERN DIGITAL COM 958102105 143,030 1,440 1.02 10,179 7.69 2.5549
2021-05-17 2021-03-31 13F WESTERN DIGITAL COM 958102105 141,590 -2,450 -1.70 9,452 18.46 2.3850
2021-02-16 2020-12-31 13F WESTERN DIGITAL COM 958102105 144,040 -2,525 -1.72 7,979 48.95 2.3282
2020-11-16 2020-09-30 13F WESTERN DIGITAL COM 958102105 146,565 34,270 30.52 5,357 8.05 2.0667
2020-08-14 2020-06-30 13F WESTERN DIGITAL COM 958102105 112,295 -39,286 -25.92 4,958 -21.41 2.1344
2020-05-15 2020-03-31 13F WESTERN DIGITAL COM 958102105 151,581 -3,115 -2.01 6,309 -35.75 3.7032
2020-02-14 2019-12-31 13F WESTERN DIGITAL COM 958102105 154,696 -34,877 -18.40 9,819 -13.15 3.1319
2020-02-25 2019-09-30 13F/A-1 WESTERN DIGITAL COM 958102105 189,573 568 0.30 11,306 25.80 3.4477
2019-11-14 2019-09-30 13F WESTERN DIGITAL COM 958102105 189,573 568 11,306 3,446,289.2798
2019-08-14 2019-06-30 13F WESTERN DIGITAL COM 958102105 189,005 -6,140 -3.15 8,987 -4.18 3.1299
2019-05-14 2019-03-31 13F WESTERN DIGITAL COM 958102105 195,145 -6,180 -3.07 9,379 26.01 3.3085
2019-02-14 2018-12-31 13F WESTERN DIGITAL COM 958102105 201,325 144,310 253.11 7,443 122.98 2.9126
2018-11-14 2018-09-30 13F WESTERN DIGITAL COM 958102105 57,015 1,871 3.39 3,338 -21.81 0.8789
2018-08-07 2018-06-30 13F WESTERN DIGITAL COM 958102105 55,144 -865 -1.54 4,269 -17.40 1.1123
2018-05-15 2018-03-31 13F WESTERN DIGITAL COM 958102105 56,009 -325 -0.58 5,168 15.36 1.4300
2018-02-08 2017-12-31 13F WESTERN DIGITAL COM 958102105 56,334 -160 -0.28 4,480 -8.22 1.1683
2017-11-13 2017-09-30 13F WESTERN DIGITAL COM 958102105 56,494 -436 -0.77 4,881 -2.73 1.3389
2017-08-09 2017-06-30 13F WESTERN DIGITAL COM 958102105 56,930 -510 -0.89 5,018 5.84 1.5115
2017-05-11 2017-03-31 13F WESTERN DIGITAL COM 958102105 57,440 510 0.90 4,741 22.57 1.4003
2017-02-14 2016-12-31 13F WESTERN DIGITAL COM 958102105 56,930 75 0.13 3,868 16.37 1.1781
2016-11-09 2016-09-30 13F WESTERN DIGITAL COM 958102105 56,855 -350 -0.61 3,324 22.93 1.1404
2016-08-11 2016-06-30 13F WESTERN DIGITAL COM 958102105 57,205 57,205 2,704 0.9743
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.