Japan's soaring AI stocks push smaller firms out of Topix index

Slashed roster likely on bigger market caps of Kioxia, Murata Manufacturing

At one point in 2026, Kioxia Holdings' market cap was more than 10 times its value in late 2025. (Photo by Shintaro Ino)

TOKYO -- Japan's broad Topix index is on track to have significantly fewer components as small- and midcap shares are pushed out by structural reforms and the soaring market capitalizations of memory chip maker Kioxia Holdings and other companies related to artificial intelligence.