It took SoftBank years of aggressive AI bets to overtake Toyota as Japan’s most valuable company. It took about a week to lose that crown.
Shares in SoftBank Group plunged roughly 20% over the course of a week in early June 2026, erasing close to $50 billion, or 5 trillion yen, in market capitalization. The collapse came just days after the company reached a historic milestone.
From record highs to a brutal reversal
On or around June 1, SoftBank’s shares surged 14% in a single session, propelling the firm past Toyota to claim the title of Japan’s most valuable public company. At its peak, SoftBank’s market cap exceeded 48 trillion yen, driven largely by investor enthusiasm for its massive AI portfolio.
Before the sell-off, the stock had climbed roughly 90% year-to-date in 2026.
