Son is the founder and largest shareholder of SoftBank, a Japanese mobile phone and investment group. The Tokyo-based company owns stakes in various technology businesses including Alibaba and Yahoo Japan. Its flagship investment arm Vision Fund posted a 4.3 trillion yen ($32 billion) loss for the year to March 31, 2023.
The majority of Son's wealth comes from his stake in technology investment company SoftBank Group.
Son controls a 35% stake directly, and through holding companies, according to the company's quarterly report as of Sept. 30, 2023 and a pledged-share filing dated Feb 20, 2023. Son has pledged more than one-third of his holdings as collateral against loans with close to 20 financial institutions. All SoftBank shares held as collateral have been excluded from his net worth calculation.
Son's liabilities were updated on May 16, 2024 to reflect losses payable on his stakes in units within SB Northstar, Vision Fund 2 and Latam fund, based on SoftBank's Mar. 31, 2024 financial report.
Son owns residential property in Tokyo, which is valued at $45 million, according to Mitsuo Hashimoto, president of Housing Japan. Son bought property in California for $117.5 million in November 2012, according to press reports at the time.
A spokesperson for SoftBank Group declined to comment on the billionaire's net worth.
Son was born in Tosu, on the Japanese island of Kyushu, to a Korean immigrant family in 1957. He was the second of four brothers. His father worked at fisheries, farms, restaurants and pachinko game parlors. Because of rampant discrimination against Korean immigrants, the family adopted the Japanese surname Yasumoto in order to assimilate. Still, Son recalled being pelted with stones in grade school by Japanese classmates, according to an autobiography.
Son, 16, met his idol, Den Fujita, the founder of McDonald's Japan and author of a bestseller book that he admired. During their 15-minute meeting, Fujita advised Son to pursue a career in the computer industry as it was the future. Son moved to San Francisco and enrolled in high school. He assumed his Korean name, and entered the University of California at Berkeley. A 1975 Popular Science cover story on the microchip inspired Son to study computer science along with economics. He made his first fortune by inventing a multilingual translator and then selling it to Sharp for about $1 million. He parlayed it by importing the Space Invaders game machines from Japan and leasing them throughout the Berkeley campus.
He returned to Japan with a bachelor's degree in economics and created SoftBank, first as a software distributor and computer magazine publisher. In the late 1980s, Son offered a system enabling fixed-line phone users to choose operators with the cheapest rates, challenging the dominance of NTT. SoftBank, in an effort to launch a full-scale Internet business in Japan, established Yahoo Japan in 1996 after investing in Yahoo in the U.S. a year before. It also bought a controlling stake in online broker E*Trade Group.
Son introduced SoftBank's broadband Internet service to Japan in 2001, wooing customers with free modems and prices that undercut NTT. By 2006, he bought Vodafone Japan for $17.5 billion in cash and debt, borrowing $11.2 billion from seven banks to fund the acquisition. He renamed the unit Softbank Mobile, which had less than 16 million mobile subscribers. Through Son's friendship with Steve Jobs, SoftBank became the exclusive supplier of iPhones in Japan. That helped double its operating margin to 21 percent by 2012, and increase mobile subscribers to 30 million.
He donated $125 million and his future salary until retirement to help victims of Japan's worst earthquake, tsunami and nuclear disaster in 2011. He also plans to build solar farms across Japan to generate electricity to replace nuclear power using a SoftBank unit, SB Energy. Son negotiated to buy a 70 percent stake in Sprint Nextel for $20.1 billion in October 2012.
The billionaire knows Bill Gates, Larry Ellison, Rupert Murdoch and Tadashi Yanai, according to an April 2014 Nikkei report. Gates would make Son's 26th-story office in Shiodome his first stop when he visits Tokyo, while Ellison invited Son to his Silicon Valley home where he met Jobs, Nikkei said.