Western Digital Corporation
CH ˙ BRSE ˙ US9581021055
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT
SecurityCH:12355 / Western Digital Corporation
InstitutionAndra AP-fonden
Latest Disclosed Ownership81,737 shares
Latest Disclosed Value $ 22,109,041
Andra AP-fonden ownership in 12355 / Western Digital Corporation

On May 8, 2026 - Andra AP-fonden filed a 13F-HR form disclosing ownership of 81,737 shares of Western Digital Corporation (CH:12355) valued at $22,109,041 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 260,400 shares of Western Digital Corporation. This represents a change in shares of -68.61% during the quarter.

Andra AP-fonden has a history of taking positions in derivatives of the underlying security (12355) in the form of stock options.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

CH:12355 / Western Digital Corporation Historical Put/Call Ratio
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)
2026-05-08 2026-03-31 13F WESTERN DIGITAL COM 958102105 81,737 -178,663 -68.61 22,109 -50.71 0.2634
2026-02-12 2025-12-31 13F WESTERN DIGITAL COM 958102105 260,400 -15,246 -5.53 44,859 35.55 0.5542
2025-11-12 2025-09-30 13F WESTERN DIGITAL COM 958102105 275,646 159,056 136.42 33,094 343.62 0.4229
2025-08-06 2025-06-30 13F WESTERN DIGITAL COM 958102105 116,590 116,590 7,461 0.1038
2025-05-13 2025-03-31 13F WESTERN DIGITAL COM 958102105 0 -26,400 -100.00 0 -100.00
2025-02-07 2024-12-31 13F WESTERN DIGITAL COM 958102105 26,400 -179,200 -87.16 1,574 -88.79 0.0252
2024-11-12 2024-09-30 13F WESTERN DIGITAL COM 958102105 205,600 174,000 550.63 14,040 486.47 0.2068
2024-08-07 2024-06-30 13F WESTERN DIGITAL COM 958102105 31,600 31,600 2,394 0.0402
2023-11-09 2023-09-30 13F WESTERN DIGITAL COM 958102105 0 -87,500 -100.00 0 -100.00
2023-08-09 2023-06-30 13F WESTERN DIGITAL COM 958102105 87,500 6,100 7.49 3,319 8.22 0.0840
2023-05-12 2023-03-31 13F WESTERN DIGITAL COM 958102105 81,400 -69,800 -46.16 3,066 76,550.00 0.0798
2023-02-13 2022-12-31 13F WESTERN DIGITAL COM 958102105 151,200 65,500 76.43 5 -99.86 0.1446
2022-11-14 2022-09-30 13F WESTERN DIGITAL COM 958102105 85,700 19,500 29.46 2,790 -6.00 0.0914
2022-08-15 2022-06-30 13F WESTERN DIGITAL COM 958102105 66,200 -25,100 -27.49 2,968 -50.15 0.0850
2022-02-15 2021-12-31 13F WESTERN DIGITAL COM 958102105 91,300 800 0.88 5,954 16.56 0.1213
2021-11-12 2021-09-30 13F WESTERN DIGITAL COM 958102105 90,500 13,500 17.53 5,108 -6.79 0.1051
2021-08-16 2021-06-30 13F WESTERN DIGITAL COM 958102105 77,000 7,100 10.16 5,480 17.45 0.1119
2021-05-17 2021-03-31 13F WESTERN DIGITAL COM 958102105 69,900 27,200 63.70 4,666 97.29 0.1029
2021-02-12 2020-12-31 13F WESTERN DIGITAL COM 958102105 42,700 -60,900 -58.78 2,365 -37.55 0.0522
2020-11-12 2020-09-30 13F WESTERN DIGITAL COM 958102105 103,600 -44,300 -29.95 3,787 -42.01 0.1027
2020-08-06 2020-06-30 13F WESTERN DIGITAL COM 958102105 147,900 39,100 35.94 6,530 44.21 0.1900
2020-05-13 2020-03-31 13F WESTERN DIGITAL COM 958102105 108,800 29,100 36.51 4,528 -10.50 0.1646
2020-02-10 2019-12-31 13F WESTERN DIGITAL COM 958102105 79,700 17,200 27.52 5,059 35.70 0.1447
2019-11-19 2019-09-30 13F WESTERN DIGITAL COM 958102105 62,500 -9,700 -13.43 3,728 8.59 0.1108
2019-08-15 2019-06-30 13F WESTERN DIGITAL COM 958102105 72,200 -26,200 -26.63 3,433 -27.41 0.0988
2019-05-14 2019-03-31 13F WESTERN DIGITAL COM 958102105 98,400 10,400 11.82 4,729 -8.21 0.1377
2018-10-16 2018-09-30 13F WESTERN DIGITAL COM 958102105 88,000 25,400 40.58 5,152 6.31 0.1328
2018-08-17 2018-06-30 13F WESTERN DIGITAL COM 958102105 62,600 -900 -1.42 4,846 -17.29 0.1310
2018-04-10 2018-03-31 13F WESTERN DIGITAL COM 958102105 63,500 19,500 44.32 5,859 67.45 0.1518
2018-02-14 2017-12-31 13F WESTERN DIGITAL COM 958102105 44,000 2,700 6.54 3,499 -1.93 0.0794
2017-10-31 2017-09-30 13F WESTERN DIGITAL COM 958102105 41,300 1,300 3.25 3,568 0.68 0.0835
2017-08-08 2017-06-30 13F WESTERN DIGITAL COM 958102105 40,000 1,000 2.56 3,544 10.10 0.0877
2017-05-15 2017-03-31 13F WESTERN DIGITAL COM 958102105 39,000 33,400 596.43 3,219 744.88 0.0755
2017-02-13 2016-12-31 13F WESTERN DIGITAL COM 958102105 5,600 -13,400 -70.53 381 -65.71 0.0104
2016-11-14 2016-09-30 13F WESTERN DIGITAL COM 958102105 19,000 -40,808 -68.23 1,111 -60.70 0.0298
2016-08-12 2016-06-30 13F WESTERN DIGITAL COM 958102105 59,808 -492 -0.82 2,827 -0.77 0.0722
2016-05-04 2016-03-31 13F WESTERN DIGITAL COM 958102105 60,300 8,700 16.86 2,849 -8.07 0.0746
2016-02-10 2015-12-31 13F WESTERN DIGITAL COM 958102105 51,600 9,300 21.99 3,099 -7.77 0.0885
2015-11-12 2015-09-30 13F WESTERN DIGITAL COM 958102105 42,300 8,700 25.89 3,360 27.51 0.0984
2015-08-13 2015-06-30 13F WESTERN DIGITAL COM 958102105 33,600 4,200 14.29 2,635 -1.53 0.0761
2015-05-14 2015-03-31 13F WESTERN DIGITAL COM 958102105 29,400 29,400 0.00 2,676 0.0758
2015-02-13 2014-12-31 13F WESTERN DIGITAL COM 958102105 0 -47,400 -100.00 0 -100.00
2014-11-12 2014-09-30 13F WESTERN DIGITAL COM 958102105 47,400 2,600 5.80 4,613 11.56 0.1082
2014-07-09 2014-06-30 13F WESTERN DIGITAL COM 958102105 44,800 -8,800 -16.42 4,135 -15.99 0.0907
2014-05-13 2014-03-31 13F WESTERN DIGITAL COM 958102105 53,600 -93,300 -63.51 4,922 -60.06 0.1135
2014-02-05 2013-12-31 13F WESTERN DIGITAL COM 958102105 146,900 -27,900 -15.96 12,325 11.22 0.2908
2013-11-07 2013-09-30 13F WESTERN DIGITAL COM 958102105 174,800 107,500 159.73 11,082 165.18 0.2826
2013-07-18 2013-06-30 13F WESTERN DIGITAL COM 958102105 67,300 67,300 4,179 0.1087
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2015-05-14 2015-03-31 13F WESTERN DIGITAL COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2015-02-13 2014-12-31 13F WESTERN DIGITAL COM Put 32,500 3,598 n/a n/a n/a
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.