Shares of hard disk drive companies fell after a report that Toshiba is planning to double its production capacity in fiscal year 2027 in response to HDD shortages, according to a Citi analyst note.

The Citi analyst noted that Toshiba, which holds approximately 10% share of HDD exabyte capacity, differs from competitors Seagate Technology (STX) and Western Digital (WDC) in that it does not internally source its own media and heads. To double its exabyte capacity, Toshiba would also require its external component suppliers to significantly raise their own capacity, which the analyst said "could limit the impact of total EB supplied to the market."

The analyst also noted that Toshiba has historically lagged behind STX and WDC on maximum capacity drives, with 30-34TB samples currently shipping and a 40TB drive launch planned for 2027, citing Trendforce data from July 2026.

The initial capacity expansion report was published by Trendforce on October 2, 2026.