For one brief moment in February 2000, Masayoshi Son was the richest man in the world. SoftBank’s stock had gone vertical on dot-com mania, and the Japanese founder’s fortune swelled to roughly $76 billion — more than Bill Gates, more than anyone else alive. It remains one of the most astonishing wealth spikes in financial history. And then came one of the most astonishing collapses.
When the bubble burst, SoftBank’s shares cratered by about 98 percent, and Son personally lost something like $70 billion — the largest destruction of an individual fortune ever recorded at the time. Headlines buried him. Silicon Valley snickered. But writing off Masayoshi Son has always been a losing trade. Two and a half decades later, he is once again one of the planet’s wealthiest people, having gone all-in on artificial intelligence with a bet that dwarfs everything that came before.
Then: The Outsider
Born on August 11, 1957, in Tosu, on Japan’s southern island of Kyushu, Son grew up as an outsider twice over: the son of a Zainichi Korean family in a country where ethnic Koreans faced open discrimination. Classmates mocked him; doors stayed shut. He responded the way he would for the rest of his life — by aiming somewhere bigger.
At 16, Son moved to California largely on his own, finished high school there, and enrolled at UC Berkeley, where he studied economics and computer science. As a student he invented an electronic translator and sold the patent to Sharp for roughly $1 million — seed money for an empire, earned before he could legally drink.
Middle: The Bets
In 1981, Son founded SoftBank as a modest software distributor in Tokyo. Within two decades it had become Japan’s internet gateway: he built Yahoo! Japan into the country’s dominant portal and, in 2000, wired $20 million to a scrappy Chinese startup called Alibaba. That single check — one of the greatest venture bets ever made — would eventually be worth tens of billions.
Son never learned to bet small. He spent $21.6 billion buying Sprint in 2013, then $32 billion on British chip designer ARM in 2016 — Britain’s biggest-ever tech deal. In 2017 he unveiled the $100 billion Vision Fund, the largest private investment vehicle in history. It made him a kingmaker — and then a cautionary tale, as more than $16 billion poured into WeWork before its 2023 bankruptcy, alongside a string of record fund losses. His approach was the photographic negative of the patient value investing preached by Warren Buffett — Son wanted to move fast and own the future outright.
Now: The AI All-In
The future, Son decided, is artificial intelligence — and he is financing that conviction with everything he has. In late 2025 he sold SoftBank’s entire stake in Nvidia, the chip giant run by Jensen Huang, worth about $5.8 billion, telling reporters he parted with the shares ‘with tears in his eyes’ — because the money had a higher calling: OpenAI. Son’s total commitment to the ChatGPT maker reached $64.6 billion for roughly a 13 percent stake, with the final $10 billion transferred on October 1, 2026. Nobody in tech history has written a bigger check to a single company.
He is not stopping there. SoftBank raised $11.1 billion in junk bonds in September 2026 — one of the largest such offerings ever — to keep the AI war chest full, and Son has been quietly pursuing ‘Project Izanagi,’ a reported $100 billion effort to build an AI chip challenger to Nvidia and the AMD empire of Lisa Su. The market has bought in: in early June 2026, SoftBank’s market value overtook Toyota’s, making it Japan’s most valuable company for the first time in 23 years, and Son’s personal fortune surged past $50 billion — with some estimates putting it above $100 billion, briefly reclaiming the title of Asia’s richest person.
Even Son is sounding notes of caution. In October 2026 he appeared alongside U.S. science adviser Michael Kratsios at Kyoto’s Science and Technology in Society forum to warn that AI could become ‘super dangerous’ — a striking moment of restraint from the man who has bet more on the technology than anyone alive, and one who once watched a $70 billion fortune evaporate in months. Perhaps only someone who has lost everything understands what is truly at stake.
Married to Masami Ohno, the father of two daughters, and a longtime Tokyo resident, Son remains what he has always been: the outsider who refuses to hedge. From the richest man on Earth to the biggest loser in market history to the biggest backer of the AI age — Masayoshi Son’s ‘then and now’ is not a simple before-and-after. It is a before, an after, and then another before, still being written.