Western Digital Corporation WDC

The business

Western Digital now makes one thing: hard disk drives, the spinning magnetic platters that store data cheaply. After separating the Sandisk flash business in February 2025, 89% of revenue comes from high-capacity drives sold to cloud operators, with 6% client and 5% consumer.

The reason this matters is that artificial-intelligence data centres need somewhere to keep enormous quantities of data that is accessed rarely. Flash is faster and far more expensive per terabyte. For cold storage at scale, spinning disks remain the only economic answer, and only three companies make them.