How SoftBank’s Masayoshi Son Lost the Title of Asia’s Richest Person in Just Three Days

On Thursday, June 4, 2026, a brutal sell-off in Tokyo erased the brief, triumphant reign of Masayoshi Son as Asia’s wealthiest individual. SoftBank Group shares plummeted 11.28%, their largest single-day drop of the year, closing at ¥7,377 . The crash was a dramatic reversal of fortune for Son, who had publicly dismissed correction fears just three days earlier. This sharp decline not only vaporized billions in personal wealth but also cast a harsh spotlight on the financial fragility underpinning SoftBank’s all-in bet on artificial intelligence.

The Immediate Trigger: A Global AI Contagion

The sell-off wasn't unique to SoftBank. It was part of a global rout in technology and AI stocks, sparked by overnight weakness spreading from U.S. markets into Asia . Investors across the board moved to reassess lofty valuations in the AI sector, leading to a wave of profit-taking. For SoftBank, already trading near a 52-week high of ¥9,074 reached just two days earlier on June 2, this sudden shift in market sentiment from euphoria to caution proved catastrophic . The company’s concentrated exposure to AI, primarily through its stakes in OpenAI and Arm Holdings, made it a primary target for traders offloading risk .

A Crown Lost in a Day

Masayoshi Son’s fall from the top of Asia’s wealth rankings was as swift as his ascent. On June 2, 2026, a 14% single-day surge in SoftBank's share price catapulted his net worth to approximately $100.7 billion on the Forbes Real-Time Billionaires List, overtaking Indian mogul Mukesh Ambani and reclaiming a title he hadn't held in over a decade . The celebrations were fleeting. When the market reversed on June 4, Son’s paper wealth cratered. Forbes estimated his net worth dropped by roughly 13% in a single trading session, wiping out approximately $13.2 billion and pulling his fortune down to about $87.1 billion . He fell behind not only Ambani but was also overtaken by Gautam Adani, who reclaimed the top spot in Asia with a net worth of $117.4 billion, and ByteDance founder Zhang Yiming, who edged out Ambani for second place .

The Debt-Fueled Gamble at the Heart of the Sell-off

Beyond the immediate market panic, the scale of Thursday’s drop underscores deep-seated investor anxiety over SoftBank’s balance sheet. The company has effectively mortgaged its future on the success of OpenAI, using a mountain of debt that is testing its own internal limits.

At the core of the concern is SoftBank’s commitment to invest more than $60 billion in OpenAI, securing approximately 13% ownership . To date, it has funneled $34.6 billion into the AI startup, including a $10 billion first-tranche investment executed in April 2026 as part of a larger $30 billion follow-on deal . To finance this, SoftBank secured a staggering $40 billion unsecured bridge loan in March 2026 from a syndicate led by JPMorgan Chase and Goldman Sachs—its largest-ever dollar-denominated borrowing, with a 12-month term that means it must be repaid or refinanced by March 2027 .

This borrowing has pushed SoftBank’s leverage to uncomfortable levels. Its total debt is projected to reach 16.3 trillion yen, breaching its self-imposed 25% loan-to-value ceiling, a concern its own CFO, Yoshimitsu Goto, has publicly acknowledged . The strain is evident: lenders recently balked at a separate planned margin loan backed by OpenAI equity, forcing SoftBank to slash the target from roughly $10 billion to $6 billion due to difficulties in valuing the still-private AI company . With the company also tapping European capital markets with euro and hybrid bonds to raise more liquidity, the market’s sudden turn against tech stocks is a direct threat to this highly leveraged structure .

"50x Bigger Than Dot-Com": Son’s Defiant Optimism Meets Reality

The most jarring element of the reversal was its timing. On June 1, the same day his net worth peaked, Masayoshi Son made a characteristically bold public statement, declaring that the AI revolution could be "50 times" the scale of the internet boom and dismissing fears of a valuation bubble . Three days later, the market delivered a stark, multi-billion-dollar rebuttal . This whiplash has crystallized the debate around Son’s legacy, leaving analysts and investors to ask whether he is "a trendsetter of his time or a bubble chaser" . The heavy reliance on an asset as speculative as OpenAI, funded by short-term borrowings, ensures that every tremor in the AI market will now translate directly into violent swings in SoftBank’s stock and its founder's personal fortune.