A month ago, Kioxia was the most valuable company in Japan, worth more than Toyota. Today, it serves as a cautionary tale about what happens when a stock rises 600%-plus on pure momentum and the momentum stops.
The NAND flash memory giant’s market cap dropped roughly 50% from its June 2026 peak, erasing approximately 29.5 trillion yen, or about $181.7B, in market value.
How Kioxia got here
The setup was straightforward: AI data centers need massive amounts of storage, and Kioxia makes the memory chips that fill those racks.
Investors extrapolated from that real demand and bid the stock up by more than 600% year-to-date heading into June 2026, with some tallies putting the gain closer to 857%.
