Kioxia, which was spun off from Toshiba in 2017, has become Japan's most valuable company by market cap.

Kioxia's Topix index weighting is set to triple after a 660% stock surge driven by AI storage demand, briefly making it Japan's most valuable company.

Bain Capital exits Kioxia with projected profits over $15 billion, closing one of private equity's most lucrative semiconductor investments since 2018.

Kioxia, which was spun off from Toshiba in 2017, has become Japan's most valuable company by market cap.