For over two decades, Toyota Motor sat comfortably atop Japan’s corporate hierarchy. That era is now over.

SoftBank Group’s market capitalization crossed ¥48 trillion, roughly $300 billion, on June 1, vaulting past Toyota’s approximately ¥46 trillion valuation. The catalyst was a 14% single-day jump in SoftBank shares during Tokyo trading, propelled by what has become the most powerful force in global markets: the insatiable appetite for anything connected to artificial intelligence.

A tale of two trajectories

The gap between these two companies didn’t open overnight. It was carved out over months, powered by radically different narratives. SoftBank’s stock has climbed between 80% and 90% since the start of the year. Toyota, meanwhile, has shed more than 10% over the same period.

This changing of the guard hasn’t happened in a meaningful, sustained way since Japan’s internet bubble peaked in 2000. Back then, SoftBank briefly claimed the top spot before the dotcom implosion brought everyone back to earth.

Masayoshi Son’s conglomerate has made substantial, tangible bets on AI infrastructure, including significant investments tied to OpenAI and ambitious plans to develop large-scale AI data center networks.

Why this matters beyond Japan

Japan’s equity market has historically been dominated by industrials, automakers, and financial conglomerates. SoftBank’s ascent represents a fundamental reordering of that hierarchy.

The broader Tokyo stock rally on June 1 further underscores the trend. This wasn’t a SoftBank-only event. Investor enthusiasm for AI-adjacent names lifted multiple stocks, suggesting the appetite for technology exposure in Japanese equities extends well beyond a single ticker.

What this means for investors

The risk is that AI enthusiasm outpaces AI revenue. SoftBank has been here before. The Vision Fund era was marked by spectacular bets that occasionally went spectacularly wrong. WeWork remains a cautionary tale etched into every investor’s memory.