From what I have read, Toshiba's 2.5" consumer/enterprise and 3.5" enterprise HDD business was acquired from Fujitsu [1] and has nothing to do with WD/HGST. WD had to transfer some/all (reports diverge) HGST 3.5" consumer HDD assets to Toshiba on the insistence of the EU Commission.

The Toshiba/HGST thing is a little opaque to me: HGST still sells a few DeskStar HDDs, notably DeskStar NAS, and newer Toshiba 3.5" consumer HDDs (MD-series 4TB+) look more like the enterprise HDDs that Toshiba has been selling for a while [2], not like the DT01ACA... models that were relabeled HGST DeskStar 7K3000 [3], although there are also pictures of the very same MD models that do look HGST-style [4]. Makes me unsure what to buy 3.5"-wise when I want the Hitachi reliability that I am used to (buying IBM/HGST for over a decade and never had a failure).

Then again, maybe I'm just naive and Toshiba is more dependent on WD than I think.

[1] http://www.cnet.com/news/toshiba-buys-fujitsu-hard-disk-driv... [2] https://www.alternate.de/p/o/a/Toshiba_PX3009E_1HP0_4_TB__Fe... [3] http://cdn1.goughlui.com/wp-content/uploads/2013/02/IMG_4989... [4] http://www.toshiba.eu/hard-drives/internal-hard-drives/sata-...