Six months ago, Kioxia Holdings was a freshly public company finding its footing on the Tokyo Stock Exchange. Today, it’s briefly overtaken Toyota Motor as Japan’s most valuable company, with a market capitalization exceeding 45 trillion JPY, roughly $281 billion.
The Japanese memory chipmaker’s weighting in the Topix index is now set to more than triple, a direct consequence of a stock price that has surged over 660% year-to-date through early June 2026.
From IPO to index heavyweight in record time
Kioxia debuted on the Tokyo Stock Exchange in December 2025. The company’s stock has climbed more than 660% since the start of 2026, pushing its market capitalization to approximately $282.6 billion by July 2026.
That briefly made Kioxia more valuable than Toyota, a company that sells roughly 10 million vehicles per year and has been Japan’s corporate crown jewel for the better part of two decades.
