Shares of Western Digital and Seagate Technology fell after Nikkei reported that the Japanese firm Toshiba plans to double its hard-disk drive production capacity within fiscal year 2027.

As of press time, Seagate Technology had plunged nearly 15%, while Western Digital had fallen more than 13%.

Nikkei reported that Toshiba plans to invest around 60 billion yen ($380 million) to expand hard-drive production in the Philippines, adding that the expansion is Toshiba's first major HDD investment in several years.

Western Digital and Seagate lead the HDD market along with Toshiba, Nikkei reported. Both U.S.-based companies have seen their earnings and stock prices soar over the past year, as the artificial-intelligence buildout created a supply crunch for data-storage products.

Toshiba currently has just more than a 10% share of the market, as measured by storage capacity, but is targeting a 30% share in the medium term, Nikkei reported.