Western Digital Corporation
CH ˙ BRSE ˙ US9581021055
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT
SecurityCH:12355 / Western Digital Corporation
InstitutionHighTower Advisors, LLC
Latest Disclosed Ownership47,036 shares
Latest Disclosed Value $ 12,723,086
HighTower Advisors, LLC ownership in 12355 / Western Digital Corporation

On May 5, 2026 - HighTower Advisors, LLC filed a 13F-HR form disclosing ownership of 47,036 shares of Western Digital Corporation (CH:12355) valued at $12,723,086 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 6, 2026 disclosing 35,293 shares of Western Digital Corporation. This represents a change in shares of 33.27% during the quarter.

HighTower Advisors, LLC has a history of taking positions in derivatives of the underlying security (12355) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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)
2026-05-05 2026-03-31 13F WESTERN DIGITAL COM 958102105 47,036 11,743 33.27 12,723 109.29 0.0135
2026-02-06 2025-12-31 13F WESTERN DIGITAL COM 958102105 35,293 10,700 43.51 6,080 105.93 0.0066
2025-11-07 2025-09-30 13F WESTERN DIGITAL COM 958102105 24,593 -16,925 -40.77 2,953 11.14 0.0034
2025-08-11 2025-06-30 13F WESTERN DIGITAL COM 958102105 41,518 26,545 177.29 2,657 339.01 0.0033
2025-05-13 2025-03-31 13F WESTERN DIGITAL COM 958102105 14,973 -2,678 -15.17 605 -42.49 0.0008
2025-02-07 2024-12-31 13F WESTERN DIGITAL COM 958102105 17,651 917 5.48 1,053 -7.80 0.0014
2024-11-14 2024-09-30 13F WESTERN DIGITAL COM 958102105 16,734 -699 -4.01 1,141 -13.69 0.0016
2024-08-13 2024-06-30 13F WESTERN DIGITAL COM 958102105 17,433 110 0.63 1,322 12.13 0.0020
2024-05-06 2024-03-31 13F WESTERN DIGITAL COM 958102105 17,323 2,736 18.76 1,179 54.52 0.0019
2024-02-12 2023-12-31 13F WESTERN DIGITAL COM 958102105 14,587 -2,052 -12.33 763 -0.52 0.0013
2023-11-08 2023-09-30 13F WESTERN DIGITAL COM 958102105 16,639 9,367 128.81 767 176.90 0.0014
2023-08-14 2023-06-30 13F WESTERN DIGITAL COM 958102105 7,272 92 1.28 277 2.21 0.0005
2023-05-12 2023-03-31 13F WESTERN DIGITAL COM 958102105 7,180 -848 -10.56 271 9.27 0.0006
2023-02-09 2022-12-31 13F WESTERN DIGITAL COM 958102105 8,028 -1,206 -13.06 248 -15.65 0.0006
2022-11-09 2022-09-30 13F WESTERN DIGITAL COM 958102105 9,234 -37,775 -80.36 294 -86.01 0.0008
2022-08-10 2022-06-30 13F WESTERN DIGITAL COM 958102105 47,009 -118,597 -71.61 2,101 -74.06 0.0054
2022-05-12 2022-03-31 13F WESTERN DIGITAL COM 958102105 165,606 -17,650 -9.63 8,099 -32.26 0.0180
2022-02-10 2021-12-31 13F WESTERN DIGITAL COM 958102105 183,256 16,651 9.99 11,956 27.15 0.0262
2021-11-12 2021-09-30 13F WESTERN DIGITAL COM 958102105 166,605 -18,193 -9.84 9,403 -28.45 0.0252
2021-08-06 2021-06-30 13F WESTERN DIGITAL COM 958102105 184,798 -17,626 -8.71 13,141 -2.63 0.0380
2021-05-10 2021-03-31 13F WESTERN DIGITAL COM 958102105 202,424 202,424 13,496 0.0426
2021-02-10 2020-12-31 13F WESTERN DIGITAL COM 958102105 0 -170,117 -100.00 0 -100.00
2020-11-13 2020-09-30 13F WESTERN DIGITAL COM 958102105 170,117 153,398 917.51 6,203 735.98 0.0300
2020-08-10 2020-06-30 13F WESTERN DIGITAL COM 958102105 16,719 -982 -5.55 742 1.09 0.0040
2020-05-21 2020-03-31 13F WESTERN DIGITAL COM 958102105 17,701 -107,853 -85.90 734 -90.78 0.0048
2020-02-14 2019-12-31 13F WESTERN DIGITAL COM 958102105 125,554 -78,367 -38.43 7,958 -34.60 0.0470
2019-11-12 2019-09-30 13F WESTERN DIGITAL COM 958102105 203,921 -105,220 -34.04 12,168 -17.27 0.0663
2019-08-13 2019-06-30 13F WESTERN DIGITAL COM 958102105 309,141 43,668 16.45 14,708 15.35 0.0875
2019-05-15 2019-03-31 13F WESTERN DIGITAL COM 958102105 265,473 116,928 78.72 12,751 131.96 0.0852
2019-02-14 2018-12-31 13F WESTERN DIGITAL COM 958102105 148,545 76,595 106.46 5,497 30.08 0.0422
2018-11-09 2018-09-30 13F WESTERN DIGITAL COM 958102105 71,950 52,492 269.77 4,226 180.61 0.0305
2018-08-14 2018-06-30 13F WESTERN DIGITAL COM 958102105 19,458 216 1.12 1,506 -15.30 0.0118
2018-05-15 2018-03-31 13F WESTERN DIGITAL COM 958102105 19,242 -6,024 -23.84 1,778 -11.45 0.0149
2018-02-14 2017-12-31 13F WESTERN DIGITAL COM 958102105 25,266 -16,643 -39.71 2,008 -44.52 0.0165
2017-11-14 2017-09-30 13F WESTERN DIGITAL COM 958102105 41,909 -25,584 -37.91 3,619 -39.58 0.0309
2017-09-22 2017-06-30 13F/A-1 WESTERN DIGITAL COM 958102105 67,493 -47,382 -41.25 5,990 -36.76 0.0536
2017-08-14 2017-06-30 13F WESTERN DIGITAL COM 958102105 67,493 -47,382 5,990
2017-05-15 2017-03-31 13F WESTERN DIGITAL COM 958102105 114,875 -50,580 -30.57 9,472 -15.77 0.0906
2017-02-10 2016-12-31 13F WESTERN DIGITAL COM 958102105 165,455 -21,820 -11.65 11,245 2.55 0.1222
2016-11-14 2016-09-30 13F WESTERN DIGITAL COM 958102105 187,275 27,881 17.49 10,965 45.27 0.1270
2016-08-11 2016-06-30 13F WESTERN DIGITAL COM 958102105 159,394 -24,485 -13.32 7,548 -13.25 0.0955
2016-05-16 2016-03-31 13F WESTERN DIGITAL COM 958102105 183,879 132,214 255.91 8,701 180.23 0.0284
2016-05-18 2015-12-31 13F/A-1 WESTERN DIGITAL COM 958102105 51,665 48,656 1,617.02 3,105 1,199.16 0.0369
2016-02-12 2015-12-31 13F WESTERN DIGITAL COM 958102105 51,665 3,105
2015-11-16 2015-09-30 13F WESTERN DIGITAL COM 958102105 3,009 100 3.44 239 4.82 0.0032
2015-08-11 2015-06-30 13F WESTERN DIGITAL COM 958102105 2,909 -2,449 -45.71 228 -53.28 0.0037
2015-05-15 2015-03-31 13F WESTERN DIGITAL COM 958102105 5,358 -59 -1.09 488 -18.67 0.0073
2015-02-17 2014-12-31 13F WESTERN DIGITAL COM 958102105 5,417 1,060 24.33 600 41.51 0.0092
2014-11-14 2014-09-30 13F WESTERN DIGITAL COM 958102105 4,357 -6,229 -58.84 424 -56.60 0.0072
2014-08-13 2014-06-30 13F WESTERN DIGITAL COM 958102105 10,586 -6,274 -37.21 977 -36.89 0.0169
2014-05-15 2014-03-31 13F WESTERN DIGITAL COM 958102105 16,860 -2,480 -12.82 1,548 -4.62 0.0302
2014-02-14 2013-12-31 13F WESTERN DIGITAL COM 958102105 19,340 -295 -1.50 1,623 30.36 0.0334
2013-11-15 2013-09-30 13F WESTERN DIGITAL COM 958102105 19,635 19,635 1,245 0.0312
Disclosed Call 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
(%)
2019-08-13 2019-06-30 13F WESTERN DIGITAL COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2019-05-15 2019-03-31 13F WESTERN DIGITAL COM Call 4,500 2 n/a n/a n/a
2018-11-09 2018-09-30 13F WESTERN DIGITAL COM Call 0 -100.00 0 n/a n/a n/a
2018-08-14 2018-06-30 13F WESTERN DIGITAL COM Call 1,500 0.00 0 -100.00 n/a n/a n/a
2018-05-15 2018-03-31 13F WESTERN DIGITAL COM Call 1,500 6 n/a n/a n/a
2018-02-14 2017-12-31 13F WESTERN DIGITAL COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2017-11-14 2017-09-30 13F WESTERN DIGITAL COM Call 1,800 2 n/a n/a n/a
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
(%)
2026-02-06 2025-12-31 13F WESTERN DIGITAL COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2025-11-07 2025-09-30 13F WESTERN DIGITAL COM Put 3,000 8 n/a n/a n/a
2024-05-06 2024-03-31 13F WESTERN DIGITAL COM Put 0 -100.00 0 n/a n/a n/a
2024-02-12 2023-12-31 13F WESTERN DIGITAL COM Put 100 4,900.00 1 n/a n/a n/a
2023-11-08 2023-09-30 13F WESTERN DIGITAL COM Put 2 1 n/a n/a n/a
2022-08-10 2022-06-30 13F WESTERN DIGITAL COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-05-12 2022-03-31 13F WESTERN DIGITAL COM Put 1 1 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.