HGST (Hitachi Global Storage Technologies) was a manufacturer of hard disk drives, solid-state drives, and external storage products and services.
It was initially a subsidiary of Hitachi, formed through its acquisition of IBM's disk drive business. It was acquired by Western Digital in 2012. However, until October 2015, it was required to operate autonomously from the remainder of the company due to conditions imposed by Chinese regulators. Chinese regulators later permitted Western Digital to begin wider integration of HGST into its main business. By 2018, the HGST brand had been phased out, with its remaining products now marketed under the Western Digital name. (Wikipedia)