Masayoshi Son
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Masayoshi Son (孫 正義, Son Masayoshi), born August 11, 1957, is a Japanese billionaire entrepreneur and investor of Korean descent. He is the founder, chairman and chief executive officer of SoftBank Group Corp., a Tokyo-listed technology investment holding company, and serves as chairman of UK chip designer Arm Holdings and of Stargate LLC, the joint venture incorporated in 2025 to build artificial intelligence infrastructure in the United States.[^1][^2] Son is widely identified with the rise of large-scale technology investing, having put roughly $20 million into Alibaba in 2000, launched the SoftBank Vision Fund (a $100 billion investment vehicle) in 2017 with the Saudi Public Investment Fund and others, and committed up to $40 billion of SoftBank capital to OpenAI in 2025.[^3][^4][^5]
Since 2023, Son has restated SoftBank's purpose around what he calls "Artificial Super Intelligence" (ASI), arguing that AI thousands of times more capable than humans will be available within a decade. The clearest expression of that thesis is the Stargate project, announced at the White House on January 21, 2025, alongside U.S. President Donald Trump, Sam Altman of OpenAI, and Larry Ellison of Oracle. Stargate is structured as a $500 billion, four-year program to build AI data centers in the United States, with SoftBank holding financial responsibility, OpenAI holding operational responsibility, and Abu Dhabi-based MGX as a co-founding equity backer.[^6][^7]
| Field | Detail |
|---|---|
| Full name | Masayoshi Son (孫 正義); birth name Masayoshi Yasumoto (安本 正義) |
| Born | August 11, 1957 |
| Birthplace | Tosu, Saga Prefecture, Japan |
| Citizenship | Japanese |
| Ethnicity | Zainichi Korean (third-generation) |
| Education | Serramonte High School (Daly City, California); University of California, Berkeley, B.A. Economics, 1980 |
| Spouse | Masami Ohno (married 1979) |
| Children | Two daughters |
| Primary residence | Tokyo (with a second home in Woodside, California) |
| Title | Founder, Chairman and CEO, SoftBank Group Corp.; Chairman, Arm Holdings; Chairman, Stargate LLC |
| Net worth | $55.1 billion (Bloomberg Billionaires Index, October 29, 2025) |
Forbes ranked Son 65th on its 2025 World's Billionaires list as of May 2025.[^8] Bloomberg's index recorded a 248% gain in his fortune across 2025, lifting him past Tadashi Yanai of Fast Retailing on October 29, 2025 to become Japan's richest person, with Bloomberg's tracker excluding any SoftBank shares pledged as loan collateral from the calculation.[^9]
Son was born in 1957 in a shack in the city of Tosu, in Saga Prefecture on the southern Japanese island of Kyushu. His grandfather, Son Jong-kyung, was a Korean from Daegu who had moved to Japan during the colonial period and worked as a coal miner in Kyushu.[^1] Son's parents were Zainichi Korean (ethnic Koreans permanently resident in Japan), and the family operated a fish farm and a pachinko parlor.
Because of widespread discrimination against Koreans in postwar Japan, Son's family used the Japanese surname Yasumoto. He was registered at school as Masayoshi Yasumoto and bullied by classmates who learned of his Korean ancestry.[^1] In a 1992 interview later quoted in Lionel Barber's The Power Law-era reporting and in Bloomberg's profile work, Son said he had thought as a child about taking his own life because of the bullying.[^9][^10]
In 1973, the teenage Son traveled to the United States for the first time on a homestay program. He returned in early 1974 and enrolled at a language school in Oakland, California, then transferred to Serramonte High School in Daly City. He passed an equivalency examination and entered the University of California, Berkeley, where he completed a degree in economics in 1980 and took computer science courses on the side.[^1][^2]
While at Berkeley, Son developed a small electronic translator with help from a team that included engineering professor Forrest Mozer of the university's space sciences laboratory. Son licensed the patent rights to Sharp Corporation; multiple later profiles report that the deal earned him roughly $1 million, though some accounts cite $1.7 million.[^11] He also imported used Japanese arcade machines (most notably Space Invaders cabinets) for installation in U.S. restaurants and dormitories, generating early operating cash that funded the founding of his Japanese company.[^1] Son met Masami Ohno, a Japanese student of medicine, at Berkeley; they married in 1979 and have two daughters.[^1]
Son has said that on returning to Japan after college, he chose to use his Korean family name Son in business, against the wishes of relatives who feared the social consequences. He later described the choice as a matter of identity rather than activism, but Japanese media frequently cite it as one of the reasons he became a public figure for the Zainichi community.[^1]
Son founded SoftBank on September 3, 1981 in Tokyo, opening the company as Nihon SoftBank, a wholesale distributor of packaged PC software.[^12] The business filled a market gap in early 1980s Japan, where personal computer hardware vendors had no central pipeline for third-party software. Son hired two part-time employees and reportedly stood on a packing crate to deliver an initial address claiming the company would one day be valued at trillions of yen.[^11]
SoftBank diversified quickly into technology publishing. In 1982 it launched two computer magazines, Oh! PC and Oh! MZ, and in 1984 it created SoftBank Commerce as a hardware distribution arm. In 1994 the company went public on the Japan over-the-counter market, raising new capital that financed an aggressive shift into the internet sector.[^12][^13]
Key acquisitions in the mid-1990s included Ziff-Davis Publishing (purchased in stages from 1995 onward) and the Comdex trade show business, both designed to give SoftBank a presence in U.S. technology media and events.[^12]
In November 1995 SoftBank invested $2 million in Yahoo!, a then-tiny U.S. portal founded by Jerry Yang and David Filo, and added a further $100 million in March 1996 in exchange for a roughly 33% stake. In April 1996, SoftBank and Yahoo! launched Yahoo Japan as a joint venture incorporated in Japan; the new entity used Yahoo! technology under license and quickly became the country's most-visited website, posting an operating profit in its first year.[^14][^15]
Later investments stretched across the dot-com sector, including stakes in E*Trade Japan, GeoCities, and a long list of U.S. start-ups. By February 2000, with internet stocks at peak valuation, SoftBank's share price had risen so far that Forbes and Japanese press reports briefly placed Son above Bill Gates among the world's wealthiest people, with paper wealth of around $78 billion. The crash that followed wiped out roughly 93% of SoftBank's market value by year-end 2000, and Son's personal fortune fell by approximately $70 billion, one of the largest individual paper losses on record.[^16]
In 2001, SoftBank pivoted into Japanese broadband. The Yahoo! BB service offered ADSL connections at prices well below NTT's incumbent rates, accumulating large subscriber numbers but also significant operating losses through its first years. Son was photographed in 2003 storming the offices of Japan's Ministry of Posts and Telecommunications to demand fairer access to NTT lines, a moment that defined his reputation as a confrontational regulator-baiter.[^11]
In April 2006 SoftBank paid roughly ¥1.75 trillion (about $15 billion at the exchange rate of the day) to acquire Vodafone's struggling Japanese mobile carrier. The transaction was the largest debt-financed buyout in Japanese history at the time, and Son funded it with high-yield bonds and equity that left SoftBank's balance sheet thinly capitalized.[^11]
Son has said in interviews and in his 2014 SoftBank World keynote that he had pitched Apple co-founder Steve Jobs on a smartphone partnership two years before the iPhone launch, sketching what he wanted on a notepad. Once SoftBank Mobile was operating, Son secured Japanese exclusivity for the iPhone, which began selling in Japan on July 11, 2008. SoftBank Mobile's market share rose from roughly 17% at the time of the Vodafone deal to about 23% by September 2011, when exclusivity ended.[^17]
In July 2013 SoftBank completed the acquisition of a 78% stake in U.S. mobile carrier Sprint Corporation for approximately $21.6 billion. The deal made Sprint a SoftBank subsidiary but exposed SoftBank to years of operating losses as Sprint struggled to compete with Verizon and AT&T.[^18] An attempted Sprint-T-Mobile merger in 2014 was abandoned after U.S. regulators signaled opposition.
A renewed merger agreement, announced in April 2018, finally closed on April 1, 2020, creating the new T-Mobile US in an all-stock deal valued at roughly $26 billion. SoftBank emerged with a roughly 24% stake (later reduced as it sold shares to fund Vision Fund commitments).[^19]
In October 1999 Son met Alibaba co-founder Jack Ma in Beijing during a SoftBank-organized session for Chinese internet entrepreneurs. Ma, then running a small Hangzhou-based business-to-business website with no revenue, said the meeting lasted six minutes. SoftBank initially agreed to invest $20 million in early 2000 in exchange for an approximately one-third stake.[^20]
The holding became one of the most profitable single venture-capital positions in history. By Alibaba's New York IPO on September 19, 2014, SoftBank's stake (then about 34%) was worth roughly $75 billion. SoftBank gradually liquidated the position from 2016 onward, using prepaid forward contracts and direct sales; by 2024 SoftBank had effectively exited Alibaba, having generated cumulative cash proceeds in the high tens of billions of dollars from the original $20 million investment.[^21] Son resigned from Alibaba's board in June 2020.
On October 14, 2016 SoftBank and Saudi Arabia's Public Investment Fund signed a memorandum of understanding to launch a technology investment vehicle. On May 20, 2017 the SoftBank Vision Fund announced its first major close at $93 billion of committed capital, with a target of $100 billion. PIF committed up to $45 billion, SoftBank $28 billion, and the United Arab Emirates' Mubadala $15 billion, with smaller commitments from Apple, Foxconn, Qualcomm, and Sharp.[^4][^22]
Vision Fund 1 made very large checks (frequently $500 million or more per company), and within four years had built positions in Uber, DiDi, DoorDash, Slack, Coupang, Bytedance, WeWork, Arm, Flexport, and dozens of other companies.[^22]
Son announced Vision Fund 2 on July 26, 2019 with a target of around $108 billion. Following the WeWork debacle later that year, the external investors who had been expected to participate withdrew, and Vision Fund 2 ended up financed almost entirely by SoftBank itself. By the company's own filings, committed capital to Vision Fund 2 has settled at roughly $56 billion, all from SoftBank.[^22][^23]
The most-discussed Vision Fund position was the office-leasing company WeWork. SoftBank invested an initial $4.4 billion in 2017 and later poured in additional equity and debt; total commitments grew to roughly $16 billion. In early 2019 Son led a financing that valued WeWork at $47 billion. The company's S-1 filing later that year exposed substantial losses and governance issues, the IPO was withdrawn in September 2019, and SoftBank had to extend a roughly $9.5 billion rescue package. After WeWork's November 2023 Chapter 11 bankruptcy, SoftBank disclosed combined losses of roughly $11.5 billion in equity and $2.2 billion in debt on the position.[^24]
The Vision Fund segment has cycled between very large gains and very large losses since 2017.
| Fiscal year (ended March 31) | Vision Fund segment result |
|---|---|
| FY2018 | Investment gain of ¥1.26 trillion |
| FY2019 | Investment loss of ¥1.93 trillion (WeWork, Uber writedowns) |
| FY2020 | Investment gain of ¥6.29 trillion (Coupang IPO, public-market rally) |
| FY2021 | Investment loss of ¥2.55 trillion |
| FY2022 | Investment loss of ¥3.50 trillion (~$27 billion) |
| FY2023 | Investment loss of ¥4.30 trillion (~$32 billion) |
| FY2024 | Annual loss as gains slowed roughly 40% from prior year |
Figures drawn from SoftBank Group consolidated financial reports filed with the Tokyo Stock Exchange and reported by Bloomberg, Reuters, and CNBC.[^25][^26]
On July 18, 2016 SoftBank announced an all-cash recommended offer to acquire UK-based Arm Holdings for £24.3 billion (approximately $32 billion at the prevailing exchange rate). The transaction completed on September 5, 2016 and made Arm a wholly owned SoftBank subsidiary.[^27]
In September 2020 SoftBank announced an agreement to sell Arm to Nvidia in a stock-and-cash deal initially valued at $40 billion, which would have grown in value as Nvidia's share price rose. Antitrust pushback in the United States, the United Kingdom, the European Union, and China led to the deal's abandonment in February 2022.[^28]
Arm went public on the Nasdaq on September 14, 2023, pricing 95.5 million American depositary shares at $51 each and raising $4.87 billion. The IPO valued Arm at $54.5 billion. SoftBank retained roughly 90% of Arm's shares after the offering and remains the controlling shareholder.[^29] Arm's stock subsequently rose substantially in 2024 and 2025 on demand for AI training chips, taking SoftBank's stake into the hundreds of billions of dollars at peak valuation and pushing SoftBank Group's own share price to its first record high in 24 years in July 2024.[^30]
Son began publicly framing SoftBank's mission around AI in early 2023, telling investors he had concluded that AGI (artificial general intelligence) and then ASI (artificial super intelligence) would arrive within his planning horizon. He referenced ASI in the SoftBank World 2023 keynote in October 2023 and repeated and expanded the thesis at the SoftBank World 2024 event the following year.[^31]
SoftBank participated in OpenAI's late-2024 tender offer at a $157 billion valuation, then on January 31, 2025 announced an investment commitment of up to $40 billion in OpenAI at a $300 billion post-money valuation. The first $7.5 billion tranche closed in April 2025, channeled through SoftBank Vision Fund 2; a second tranche of $22.5 billion closed on December 26, 2025 (U.S. time), bringing SoftBank's direct contribution to $30 billion alongside $11 billion from third-party co-investors.[^5][^32]
In parallel, on February 3, 2025 SoftBank Group, SoftBank Corp., and OpenAI announced a Japan-focused enterprise AI partnership called "Cristal Intelligence" and a joint venture, SB OpenAI Japan, to market the product to Japanese enterprises. SoftBank Group committed to spending $3 billion per year deploying OpenAI products across its operating companies, becoming the first company to integrate Cristal Intelligence at scale. SB OAI Japan GK was incorporated on November 5, 2025, with public availability of Cristal Intelligence planned for 2026.[^33][^34]
On January 21, 2025, the day after his second inauguration, U.S. President Donald Trump appeared in the Roosevelt Room at the White House with Son, Sam Altman, and Larry Ellison to announce the Stargate Project, a new American company to build AI infrastructure for OpenAI in the United States.[^6][^7] The announcement specified:
The first Stargate site, in Abilene, Texas, broke ground in early 2025, and on September 24, 2025 OpenAI, Oracle, and SoftBank disclosed five additional sites and stated that the joint venture was on a path to deploy the full $500 billion, 10-gigawatt commitment by the end of 2025, ahead of the original schedule.[^35]
| Year | Event |
|---|---|
| 1981 | Founds SoftBank in Tokyo as a packaged-software distributor (September 3) |
| 1994 | SoftBank IPO on the Japanese OTC market |
| 1995 | Initial $2 million investment in Yahoo! |
| 1996 | Co-founds Yahoo Japan |
| 2000 | Invests roughly $20 million in Alibaba; SoftBank market value collapses with the dot-com bust |
| 2001 | Launches Yahoo! BB ADSL service |
| 2006 | Acquires Vodafone Japan for about $15 billion |
| 2008 | Begins iPhone sales in Japan under SoftBank Mobile (July 11) |
| 2013 | Acquires 78% of Sprint for about $21.6 billion |
| 2016 | Acquires Arm Holdings for £24.3 billion (September 5) |
| 2017 | Vision Fund 1 first major close at $93 billion (May 20) |
| 2019 | Announces Vision Fund 2 (July 26); WeWork IPO collapses (September) |
| 2020 | Sprint–T-Mobile merger closes (April 1); exits Alibaba board (June) |
| 2022 | Nvidia–Arm deal abandoned (February); Vision Fund posts ¥3.5 trillion loss |
| 2023 | Vision Fund posts ¥4.3 trillion loss; Arm IPO at $54.5 billion valuation (September 14) |
| 2025 | Stargate announced at the White House (January 21); $40 billion OpenAI commitment (January 31); Cristal Intelligence and SB OpenAI Japan announced (February 3); Bloomberg index marks Son as Japan's richest at $55.1 billion (October 29); $22.5 billion second OpenAI tranche closes (December 26) |
Dates and values cross-referenced with SoftBank Group press releases and the company's annual reports.[^12][^36]
Son controls roughly a 35% economic interest in SoftBank Group through directly held shares and family holding companies. He has historically pledged about a third of his shares as collateral on personal loans against close to 20 financial institutions; Bloomberg's billionaire index excludes pledged shares from its calculation, which keeps its figure lower than other estimates.[^9] His net worth on Bloomberg's tracker rose from roughly $15.8 billion at the start of 2025 to $55.1 billion on October 29, 2025, a 248% increase driven by SoftBank's share rally on the Arm holding and Stargate news.[^9] By late November 2025, after a roughly $5 billion single-day decline, the Forbes Real-Time Billionaires page placed him at the world's 32nd-wealthiest person at $49.3 billion.[^37]
Son publishes long strategic decks at the company's annual investor events, the most-cited of which are SoftBank's "Next 30-Year Vision" (released in 2010) and the "300-year vision plan" Son references in interviews. The 2010 deck described, in often-mocked detail, possible technologies of the year 2310, including telepathic neural chips and machine-translated communication.[^38] At SoftBank World 2023 and 2024 he described AI super-intelligence as 10,000 times more capable than the smartest human and presented timelines for AGI and ASI of "a few years" and "about a decade" respectively.[^31]
Son's verified public quotes include the line he repeated to Forbes in 2014: "Information revolution, happiness for everyone" (情報革命で人々を幸せに), which became SoftBank's official tagline. In a 2017 Bloomberg interview about Alibaba he said he had decided to invest after seeing Jack Ma's "strong, shining eyes," despite the company having no revenue and no business plan.[^20]
Following the WeWork collapse in 2019 Son told a Tokyo earnings briefing: "My investment judgment was poor in many ways and I am reflecting deeply on this," and described his prior valuation of Adam Neumann as "foolish."[^24]
The SoftBank Hawks (a Nippon Professional Baseball team based in Fukuoka) have been part of SoftBank Group since 2005, when SoftBank purchased the franchise from Daiei. Son routinely attends post-season Hawks games.
Son and Masami Ohno married in 1979 while Son was still at Berkeley; they have two daughters whose names SoftBank does not disclose publicly. The family's primary residence is a three-story Tokyo mansion that Bloomberg has reported as worth around $85 million; it includes a private indoor golf simulator that recreates climate conditions of various courses. Son also owns a Woodside, California estate purchased for $117.5 million in 2013, which was for several years among the most expensive residential transactions in U.S. history.[^39]
In the aftermath of the March 11, 2011 Tōhoku earthquake and tsunami, Son donated ¥10 billion personally and pledged his future SoftBank salary to families of the disaster victims and to children orphaned by the event. SoftBank has also funded scholarship and renewable energy initiatives through the Japan Renewable Energy Foundation, which Son founded in 2011.[^40]
Son plays golf and is an avid card and shogi player; SoftBank investor presentations frequently include analogies drawn from board games. He has cited Confederate-era Japanese reformer Sakamoto Ryōma and U.S. computer industry pioneer Sam Walton as personal influences.[^11]
| Company | Sector | SoftBank position | Notes |
|---|---|---|---|
| Alibaba | E-commerce | Exited (peak ~34%) | $20M investment in 2000; cumulative proceeds in tens of billions |
| Arm Holdings | Semiconductors | ~90% | Acquired 2016 for $32B; 2023 IPO at $54.5B valuation |
| Yahoo Japan (Z Holdings / LY Corp.) | Internet | Major | Co-founded 1996 |
| Sprint Corporation / T-Mobile US | Telecom | ~24% (T-Mobile) | Sprint acquired 2013, merged 2020 |
| OpenAI | AI | ~11% (private) | Up to $40B committed in 2025 |
| Stargate LLC | AI infrastructure | Equity / financier | $500B program announced January 2025 |
| Uber | Mobility | Exited | Vision Fund 1 sold position 2022 |
| DiDi | Mobility | Major | Vision Fund 1 |
| DoorDash | Delivery | Reduced | Vision Fund 1 |
| Slack | Software | Exited (Salesforce acquisition) | Vision Fund 1 |
| WeWork | Real estate | Substantially written off | ~$16B committed; Chapter 11 in 2023 |
| Coupang | E-commerce | Reduced | Vision Fund 1 |
| ByteDance | Social / AI | Held | Vision Fund 1 |
| Cruise | Autonomous vehicles | Exited | Sold stake to GM in 2022 |
| Boston Dynamics | Robotics | Sold to Hyundai | Acquired from Alphabet 2017; sold 2020 |
Positions and statuses based on SoftBank Group consolidated financial filings and Vision Fund quarterly reports as of fiscal year 2025.[^36]
Son has appeared on multiple Forbes and Time lists, including Forbes World's Most Powerful People (#45 in 2013) and Time 100 Most Influential People in AI in 2024.[^1] In 2018 the Japanese government awarded him the Order of the Rising Sun, Gold and Silver Star.