A Western Digital SSD bought today is a Sandisk product. Western Digital spun off its flash business as Sandisk on February 21, 2025, and per its fiscal 2026 10-K it now sells hard drives only, across its Cloud, Client and Consumer end markets.
WD_BLACK and WD Blue SSDs are Sandisk products, sold under a transitional license from Western Digital per Sandisk’s 10-K for the same year.
Which SSD lines moved to Sandisk
Sandisk’s fiscal 2026 10-K says some products “will also be sold for a limited transitional period under the Western Digital, WD and other brands under license from WDC.” The license is a filed exhibit: the Transitional Trademark License Agreement dated February 21, 2025.
The consumer rename is already under way. At CES on January 5, 2026, Sandisk announced that WD Blue NVMe drives, including the WD Blue SN5100, become the SANDISK Optimus line. WD_BLACK drives split into Optimus GX (formerly the SN7100) and Optimus GX PRO (formerly the SN8100).
Video: SANDISK Optimus
Sandisk’s enterprise SSD page lists the Ultrastar DC SN655 next to the Sandisk-branded SN861 and SN670, the last built on UltraQLC and BiCS8 NAND with capacities up to 122.88TB.
What Western Digital kept: hard drives only
Western Digital’s own 10-K for the year ended July 3, 2026 calls it “a pure-play HDD company.” It sells HDDs into Cloud, Client and Consumer end markets.
The Ultrastar name now appears on both companies’ sites. Western Digital’s data center page lists Ultrastar DC HC690 hard drives at 30TB to 32TB, while Sandisk sells Ultrastar DC SN SSDs. The name no longer tells you which company made the drive.
Product line, business unit and listing, from the filings
| Company and listing | Business unit | Product lines | FY2026 revenue, per 10-K |
|---|---|---|---|
| Sandisk, SNDK, Nasdaq | Datacenter | Enterprise NVMe SSDs: SN861, SN670, Ultrastar DC SN655 | $5,153 million |
| Sandisk, SNDK, Nasdaq | Edge | Client SSDs for PCs, consoles, set-top boxes; embedded flash for phones, cars, IoT | $12,160 million |
| Sandisk, SNDK, Nasdaq | Consumer | Retail SSDs (WD Blue and WD_BLACK, moving to Optimus), portable SSDs, cards, USB drives | $2,935 million |
| Western Digital, WDC, Nasdaq | Cloud | High-capacity enterprise HDDs, including Ultrastar DC HC | $11,490 million |
| Western Digital, WDC, Nasdaq | Client | Desktop and notebook HDDs for OEM and channel customers | $726 million |
| Western Digital, WDC, Nasdaq | Consumer | External HDD storage sold through retail | $703 million |
Source: Sandisk 10-K and Western Digital 10-K, both for the fiscal year ended July 3, 2026; product names from sandisk.com and westerndigital.com.
Why the split matters if you follow the stocks
Western Digital’s Cloud market made up 89% of its $12,919 million fiscal 2026 revenue, and its top 10 customers made up 73%. That profile is covered in our breakdown of data storage stocks.
Sandisk’s NAND-only business, per its 10-K, sits closer to the memory chip stocks group than to hard drive makers. Its Datacenter line sells enterprise NVMe SSDs into the same servers covered under AI chip stocks.
The common mistake is reading a WD_BLACK SSD sales spike as a Western Digital signal. That revenue lands in SNDK, not WDC. This is general information, not investment advice.
Frequently asked questions
Does Western Digital still make SSDs?
No. Its fiscal 2026 10-K describes it as a pure-play HDD company. WD-branded SSDs are made and sold by Sandisk under a transitional trademark license.
Is a WD_BLACK SSD the same as a SANDISK Optimus SSD?
The line is the same, renamed. Sandisk said in January 2026 that the WD_BLACK SN7100 continues as Optimus GX and the SN8100 as Optimus GX PRO, with rebranded stock reaching retailers in the first half of 2026.
Which stock gets the revenue from WD-branded SSDs?
Sandisk, ticker SNDK. Western Digital’s revenue under WDC now comes from hard drives in its Cloud, Client and Consumer end markets.
