Kioxia Holdings Corp became Japan's most valuable company by market capitalization on June 12, 2026, after its shares surged 7.6% to raise its market value above 44 trillion yen ($274 billion) [1, 2, 3, 4]. This rise surpassed Toyota Motor Corp, which closed at approximately 43.8 trillion yen ($273 billion) on the same day [1, 2, 4].
Kioxia's stock has skyrocketed more than 670% in 2026, making it the best-performing stock on the MSCI World Index this year [1, 2, 3, 4]. The rapid growth comes amid booming demand for chips driven by artificial intelligence applications. Market analyst Shuutarou Yasuda of Tokai Tokyo Intelligence Laboratory said, "It may be a bit of an exaggeration to call it an industrial transformation, but it’s a development that certainly gives that impression" [1].
Toyota’s shares have fallen around 17% in 2026. The decline has been linked to tensions in the Middle East, rising oil prices, and challenges in transitioning its auto business to electric vehicles and software development [1, 2, 4]. Earlier in June, SoftBank Group briefly overtook Toyota due to enthusiasm around its AI investments and the expected listing of OpenAI, but SoftBank fell back to fourth place after a market selloff [1, 2, 4].
Kioxia originated from Toshiba’s memory chip division, which pioneered NAND flash memory. Toshiba spun off the unit in 2018, and it was acquired by a Bain Capital-led consortium. The company rebranded as Kioxia in 2019 [1, 2, 4].
Japan’s list of top 20 companies now includes multiple AI-related firms, such as Murata Manufacturing and Advantest, involved in AI data center components and chip testing, reflecting a shift in investor focus [1, 2, 4].
On June 12, 2026, Kioxia's surge finalized its leap past Toyota, marking a key milestone in Japan's market landscape [1, 2, 3, 4].
