Western Digital Corporation
CH ˙ BRSE ˙ US9581021055
DETTE SYMBOL ER IKKE LÆNGERE AKTIVT
SecurityCH:12355 / Western Digital Corporation
InstitutionMain Street Group, LTD
Latest Disclosed Ownership244 shares
Latest Disclosed Value $ 66,000
Main Street Group, LTD ownership in 12355 / Western Digital Corporation

On May 6, 2026 - Main Street Group, LTD filed a 13F-HR form disclosing ownership of 244 shares of Western Digital Corporation (CH:12355) valued at $66,000 USD as of March 31, 2026. The entity filed a previous 13F-HR on January 26, 2026 disclosing 0 shares of Western Digital Corporation.

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)
2026-05-06 2026-03-31 13F WESTERN DIGITAL STOK 958102105 244 244 66 0.0032
2026-01-26 2025-12-31 13F WESTERN DIGITAL STOK 958102105 0 -244 -100.00 0 -100.00
2025-11-07 2025-09-30 13F WESTERN DIGITAL STOK 958102105 244 0 0.00 29 93.33 0.0086
2025-07-15 2025-06-30 13F WESTERN DIGITAL STOK 958102105 244 -518 -67.98 16 -50.00 0.0051
2025-05-14 2025-03-31 13F WESTERN DIGITAL COM Common Stock 958102105 762 518 212.30 31 114.29 0.0118
2025-02-14 2024-12-31 13F WESTERN DIGITAL STOK 958102105 244 -158 -39.30 15 -48.15 0.0054
2024-11-13 2024-09-30 13F WESTERN DIGITAL STOK 958102105 402 -216 -34.95 27 -42.55 0.0108
2024-08-06 2024-06-30 13F WESTERN DIGITAL STOK 958102105 618 -1,148 -65.01 47 -61.48 0.0196
2024-05-15 2024-03-31 13F WESTERN DIGITAL STOK 958102105 1,766 1,448 455.35 122 662.50 0.0533
2024-02-15 2023-12-31 13F WESTERN DIGITAL COMMON STOCK 958102105 318 318 17 0.0058
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.