Mücahithan Avcıoğlu
12 June 2026•Update: 12 June 2026
Japanese memory chipmaker Kioxia Holdings Corp. has overtaken Toyota Motor Corp. to become Japan’s most valuable company by market capitalization, as investor appetite for artificial intelligence-related semiconductor firms continues to reshape the country’s equity market.
Kioxia’s shares rose 7.6% on Friday, lifting the company’s market value above 44 trillion yen ($274 billion), just 18 months after its stock market debut.
Toyota, long Japan’s largest listed company, ended the session with a market capitalization of $273.1 billion, losing the top spot as its shares remained under pressure.
Kioxia’s rapid rise reflects a broader shift in global markets, where semiconductor and AI-linked companies have drawn strong inflows due to rising demand for chips used in data centers.
The company’s shares have climbed more than 670% since the beginning of the year, making it one of the world’s best-performing major stocks.
Japan’s largest listed companies now include several AI-related names, including Murata Manufacturing, a supplier of components used in data centers, and Advantest, a major producer of semiconductor testing equipment.
SoftBank Group had briefly surpassed Toyota earlier this month, supported by investor optimism over its artificial intelligence investments and expectations surrounding OpenAI’s future listing plans. However, SoftBank later slipped in the ranking after a broader risk-off move in markets.
Kioxia traces its roots to Toshiba’s memory chip business, which helped pioneer NAND flash memory technology. The unit was spun off and acquired by a Bain Capital-led consortium in 2018, before being renamed Kioxia in 2019.
Toyota’s shares, meanwhile, have fallen around 17% so far this year, weighed down by higher oil prices, Middle East tensions and concerns over the global auto sector’s transition toward electric vehicles and software-based mobility.
