Western Digital Corporation
CH ˙ BRSE ˙ US9581021055
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT
SecurityCH:12355 / Western Digital Corporation
InstitutionWalleye Capital LLC
Latest Disclosed Ownership49,189 shares
Latest Disclosed Value $ 13,305,133
Walleye Capital LLC ownership in 12355 / Western Digital Corporation

On May 13, 2026 - Walleye Capital LLC filed a 13F-HR/A form disclosing ownership of 49,189 shares of Western Digital Corporation (CH:12355) valued at $13,305,133 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 58,171 shares of Western Digital Corporation. This represents a change in shares of -15.44% during the quarter.

Walleye Capital 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 43,100 of underlying shares valued at $11,658,119 USD and put options representing 39,200 of underlying shares valued at $10,603,208 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)
2026-05-13 2026-03-31 13F/A-1 WESTERN DIGITAL COM 958102105 49,189 -8,982 -15.44 13,305 32.77 0.0554
2026-05-08 2026-03-31 13F WESTERN DIGITAL COM 958102105 49,189 -8,982 13,305 0.0553
2026-02-13 2025-12-31 13F WESTERN DIGITAL COM 958102105 58,171 -115,918 -66.59 10,021 -52.05 0.0307
2025-11-14 2025-09-30 13F WESTERN DIGITAL COM 958102105 174,089 88,349 103.04 20,901 280.99 0.0784
2025-08-13 2025-06-30 13F WESTERN DIGITAL COM 958102105 85,740 -593,869 -87.38 5,487 -80.03 0.0213
2025-05-14 2025-03-31 13F WESTERN DIGITAL COM 958102105 679,609 231,226 51.57 27,477 2.76 0.1240
2025-02-13 2024-12-31 13F WESTERN DIGITAL COM 958102105 448,383 -388,827 -46.44 26,737 -53.23 0.0653
2024-11-14 2024-09-30 13F WESTERN DIGITAL COM 958102105 837,210 484,577 137.42 57,173 113.98 0.1190
2024-08-14 2024-06-30 13F WESTERN DIGITAL COM 958102105 352,633 -8,011 -2.22 26,719 8.57 0.0477
2024-05-15 2024-03-31 13F WESTERN DIGITAL COM 958102105 360,644 -309,403 -46.18 24,610 -29.87 0.0438
2024-02-14 2023-12-31 13F WESTERN DIGITAL COM 958102105 670,047 348,553 108.42 35,090 139.21 0.0744
2023-11-21 2023-09-30 13F/A-1 WESTERN DIGITAL COM 958102105 321,494 -132,667 -29.21 14,670 -14.84 0.0375
2023-11-14 2023-09-30 13F WESTERN DIGITAL COM 958102105 321,494 -132,667 14,670 0.0377
2023-08-14 2023-06-30 13F WESTERN DIGITAL COM 958102105 454,161 -18,197 -3.85 17,226 -3.19 0.0624
2023-05-15 2023-03-31 13F WESTERN DIGITAL COM 958102105 472,358 472,358 17,794 0.2666
2022-08-19 2022-06-30 13F/A-1 WESTERN DIGITAL COM 958102105 0 -25,501 -100.00 0 -100.00
2022-08-08 2022-06-30 13F WESTERN DIGITAL COM 958102105 0 -25,501 0
2022-05-27 2022-03-31 13F/A-01 WESTERN DIGITAL COM 958102105 25,501 1,377 5.71 1,266 -19.52 0.0338
2022-05-16 2022-03-31 13F WESTERN DIGITAL COM 958102105 25,501 1,377 1,266 0.0258
2022-05-27 2021-12-31 13F/A-01 WESTERN DIGITAL COM 958102105 24,124 9,641 66.57 1,573 92.53 0.0489
2022-03-03 2021-12-31 13F WESTERN DIGITAL COM 958102105 24,124 9,641 1,573 0.0393
2021-11-15 2021-09-30 13F WESTERN DIGITAL COM 958102105 14,483 14,483 817 0.0232
2021-08-16 2021-06-30 13F WESTERN DIGITAL COM 958102105 0 -13,379 -100.00 0 -100.00
2021-05-17 2021-03-31 13F WESTERN DIGITAL COM 958102105 13,379 13,379 893 0.0517
2021-02-16 2020-12-31 13F WESTERN DIGITAL COM 958102105 0 -61,914 -100.00 0 -100.00
2020-11-16 2020-09-30 13F WESTERN DIGITAL COM 958102105 61,914 -38,334 -38.24 2,263 -48.87 0.2522
2020-08-14 2020-06-30 13F WESTERN DIGITAL COM 958102105 100,248 91,692 1,071.67 4,426 1,143.26 0.9875
2020-05-15 2020-03-31 13F WESTERN DIGITAL COM 958102105 8,556 3,213 60.13 356 5.01 0.0784
2020-02-14 2019-12-31 13F WESTERN DIGITAL COM 958102105 5,343 5,343 339 0.0220
2019-11-14 2019-09-30 13F WESTERN DIGITAL COM 958102105 0 -3,380 -100.00 0 -100.00
2019-08-14 2019-06-30 13F WESTERN DIGITAL COM 958102105 3,380 1,180 53.64 161 51.89 0.0177
2019-08-14 2019-03-31 13F/A-1 WESTERN DIGITAL COM 958102105 2,200 2,200 106 0.0175
2019-05-15 2019-03-31 13F WESTERN DIGITAL COM 958102105 2,200 106 0.0175
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
(%)
2026-05-13 2026-03-31 13F/A WESTERN DIGITAL COM Call 43,100 -44.17 11,658 -12.34 n/a n/a n/a
2026-05-08 2026-03-31 13F WESTERN DIGITAL COM Call 43,100 11,658 n/a n/a n/a
2026-02-13 2025-12-31 13F WESTERN DIGITAL COM Call 77,200 82.51 13,299 161.89 n/a n/a n/a
2025-11-14 2025-09-30 13F WESTERN DIGITAL COM Call 42,300 -42.37 5,079 8.13 n/a n/a n/a
2025-08-13 2025-06-30 13F WESTERN DIGITAL COM Call 73,400 -58.32 4,697 -34.04 n/a n/a n/a
2025-05-14 2025-03-31 13F WESTERN DIGITAL COM Call 176,100 -55.45 7,120 -69.80 n/a n/a n/a
2025-02-13 2024-12-31 13F WESTERN DIGITAL COM Call 395,300 99.45 23,572 74.15 n/a n/a n/a
2024-11-14 2024-09-30 13F WESTERN DIGITAL COM Call 198,200 -54.92 13,535 -59.37 n/a n/a n/a
2024-08-14 2024-06-30 13F WESTERN DIGITAL COM Call 439,700 105.47 33,316 128.14 n/a n/a n/a
2024-05-15 2024-03-31 13F WESTERN DIGITAL COM Call 214,000 219.40 14,603 316.28 n/a n/a n/a
2024-02-14 2023-12-31 13F WESTERN DIGITAL COM Call 67,000 -46.18 3,509 -38.24 n/a n/a n/a
2023-11-21 2023-09-30 13F/A WESTERN DIGITAL COM Call 124,500 137.60 5,681 185.86 n/a n/a n/a
2023-11-14 2023-09-30 13F WESTERN DIGITAL COM Call 124,500 5,681 n/a n/a n/a
2023-08-14 2023-06-30 13F WESTERN DIGITAL COM Call 52,400 1,178.05 1,988 1,190.26 n/a n/a n/a
2023-05-15 2023-03-31 13F WESTERN DIGITAL COM Call 4,100 154 n/a n/a n/a
2023-02-14 2022-12-31 13F WESTERN DIGITAL COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2022-11-14 2022-09-30 13F WESTERN DIGITAL COM Call 16,200 527 n/a n/a n/a
2020-08-14 2020-06-30 13F WESTERN DIGITAL COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-05-15 2020-03-31 13F WESTERN DIGITAL COM Call 1,300 -43.48 54 -63.01 n/a n/a n/a
2020-02-14 2019-12-31 13F WESTERN DIGITAL COM Call 2,300 146 n/a n/a n/a
2019-11-14 2019-09-30 13F WESTERN DIGITAL COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2019-08-14 2019-06-30 13F WESTERN DIGITAL COM Call 4,600 -6.12 219 -6.81 n/a n/a n/a
2019-08-14 2019-03-31 13F/A WESTERN DIGITAL COM Call 4,900 235 n/a n/a n/a
2019-05-15 2019-03-31 13F WESTERN DIGITAL COM Call 4,900 235 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
(%)
2026-05-13 2026-03-31 13F/A WESTERN DIGITAL COM Put 39,200 -63.30 10,603 -42.37 n/a n/a n/a
2026-05-08 2026-03-31 13F WESTERN DIGITAL COM Put 39,200 10,603 n/a n/a n/a
2026-02-13 2025-12-31 13F WESTERN DIGITAL COM Put 106,800 34.68 18,398 93.26 n/a n/a n/a
2025-11-14 2025-09-30 13F WESTERN DIGITAL COM Put 79,300 72.77 9,521 224.14 n/a n/a n/a
2025-08-13 2025-06-30 13F WESTERN DIGITAL COM Put 45,900 -37.72 2,937 -1.41 n/a n/a n/a
2025-05-14 2025-03-31 13F WESTERN DIGITAL COM Put 73,700 -78.26 2,980 -85.26 n/a n/a n/a
2025-02-13 2024-12-31 13F WESTERN DIGITAL COM Put 339,000 -10.22 20,215 -21.61 n/a n/a n/a
2024-11-14 2024-09-30 13F WESTERN DIGITAL COM Put 377,600 -7.18 25,786 -16.34 n/a n/a n/a
2024-08-14 2024-06-30 13F WESTERN DIGITAL COM Put 406,800 -25.21 30,823 -16.95 n/a n/a n/a
2024-05-15 2024-03-31 13F WESTERN DIGITAL COM Put 543,900 17.68 37,116 53.34 n/a n/a n/a
2024-02-14 2023-12-31 13F WESTERN DIGITAL COM Put 462,200 81.04 24,205 107.79 n/a n/a n/a
2023-11-21 2023-09-30 13F/A WESTERN DIGITAL COM Put 255,300 51.69 11,649 82.50 n/a n/a n/a
2023-11-14 2023-09-30 13F WESTERN DIGITAL COM Put 255,300 11,649 n/a n/a n/a
2023-08-14 2023-06-30 13F WESTERN DIGITAL COM Put 168,300 216.95 6,384 219.15 n/a n/a n/a
2023-05-15 2023-03-31 13F WESTERN DIGITAL COM Put 53,100 2,000 n/a n/a n/a
2023-02-14 2022-12-31 13F WESTERN DIGITAL COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2022-11-14 2022-09-30 13F WESTERN DIGITAL COM Put 8,100 264 n/a n/a n/a
2020-08-14 2020-06-30 13F WESTERN DIGITAL COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2020-05-15 2020-03-31 13F WESTERN DIGITAL COM Put 16,000 -1.23 666 -35.21 n/a n/a n/a
2020-02-14 2019-12-31 13F WESTERN DIGITAL COM Put 16,200 1,028 n/a n/a n/a
2019-11-14 2019-09-30 13F WESTERN DIGITAL COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2019-08-14 2019-06-30 13F WESTERN DIGITAL COM Put 1,600 433.33 76 442.86 n/a n/a n/a
2019-08-14 2019-03-31 13F/A WESTERN DIGITAL COM Put 300 14 n/a n/a n/a
2019-05-15 2019-03-31 13F WESTERN DIGITAL COM Put 300 14 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.