Big bets that built SoftBank
Masayoshi Son's fortune is tied to SoftBank Group, the company he founded in Japan in 1981 and has led ever since. SoftBank began as a distributor of personal computer software and a publisher of computer magazines. During the 1990s Son reshaped it into an investor in the young internet industry. He backed Yahoo in the United States and in 1996 formed Yahoo Japan as a joint venture, which became the dominant web portal in Japan.
His most famous investment came in 2000, when SoftBank put money into Alibaba, a small ecommerce startup led by Jack Ma. Alibaba grew into one of China's largest companies, and SoftBank's stake became enormously valuable. The dot com crash of 2000 and 2001 hit SoftBank hard, but the Alibaba holding and later telecom businesses helped the company recover.
In 2006 SoftBank bought Vodafone's Japanese mobile unit, which became SoftBank Mobile and gained customers as the exclusive Japanese carrier of the iPhone from 2008. In 2016 SoftBank acquired the British chip designer Arm, and in 2023 it relisted a minority of Arm's shares on Nasdaq while keeping control. Son holds a large stake in SoftBank Group, and the value of that stake is the source of his wealth.
SoftBank holdings and the Vision Fund
SoftBank's main assets have included:
- Arm Holdings: the chip design company whose architecture powers most smartphones
- SoftBank Corp.: the Japanese mobile and broadband carrier, listed separately in 2018
- The Vision Funds: technology investment funds launched from 2017, the first with backing from Saudi Arabia's Public Investment Fund and Abu Dhabi's Mubadala
- Investments in artificial intelligence: including a major stake in OpenAI built up from 2025
SoftBank also held large positions in Sprint, the American carrier it took over in 2013 and later merged with T-Mobile US, and in Alibaba, which it largely sold down in the early 2020s.
The Vision Fund made hundreds of investments in startups such as Uber, ByteDance and DoorDash. It also suffered high profile losses, most notably WeWork, the office sharing company whose planned public listing collapsed in 2019. Son has described his strategy as a long term bet on what he calls the information revolution. In January 2025 SoftBank joined OpenAI, Oracle and other partners in announcing Stargate, a project to build data centers for artificial intelligence in the United States.
Childhood in Kyushu and studies in California
Masayoshi Son was born in August 1957 in Tosu, in Saga prefecture on the island of Kyushu. His family was of Korean descent, and he grew up in modest circumstances. During his childhood the family used the Japanese surname Yasumoto, but he later chose to use his Korean family name, Son.
As a teenager he read a book by Den Fujita, the founder of McDonald's Japan, and met him, receiving advice to study in the United States. Son moved to California at the age of 16, finished high school quickly and studied economics at the University of California, Berkeley, graduating in 1980.
While at Berkeley he worked with professors and engineers to develop an electronic pocket translator and sold the design to the Japanese electronics company Sharp. He also imported used arcade game machines from Japan to place in restaurants and student hangouts. After graduating he founded a company in California called Unison World, then returned to Japan, where he started SoftBank the following year. He has said that he set goals for each decade of his life early on, including building a company of great scale.
Philanthropy and energy advocacy
After the March 2011 earthquake and tsunami in northeastern Japan, Son pledged a large personal donation for relief efforts and said he would donate his salary as SoftBank's chief executive until he retired. The disaster at the Fukushima nuclear plant also led him to campaign for renewable energy.
In 2011 he founded the Japan Renewable Energy Foundation, later renamed the Renewable Energy Institute, to promote solar and wind power. He also set up SB Energy to build solar plants in Japan and abroad, and he promoted an idea called the Asia Super Grid to link electricity networks across countries in the region.
In 2016 he established the Masason Foundation, which provides grants and support to talented young people with ambitious goals in science, technology and other fields. Son remains a prominent and sometimes controversial figure in global technology. Supporters credit him with spotting major trends early, while critics point to the losses at some Vision Fund companies and the debt SoftBank has used to finance its investments.