Tsai is a co-founder of Alibaba Group, China's biggest e-commerce company. The Hangzhou-based business operates Taobao, an online shopping site, and Tmall, a platform that allows companies to open and operate online stores. The group had revenue of 996 billion yuan ($138 billion) in the year to March 31, 2025.
The majority of Tsai's wealth is derived from his 1.4% stake in Alibaba Group, China's largest retail commerce business. The group had revenue of 996 billion yuan ($138 billion) in the year to March 31, 2025.
The billionaire holds the stake directly and through holding companies based in the Bahamas and British Virgin Islands, according to the company's filing to the Hong Kong stock exchange in April 2026.
Tsai acquired a 49% stake in the Brooklyn Nets basketball club from Russian billionaire Mikhail Prokhorov in 2018. The sale valued the Nets at $2.3 billion, according to an Oct. 27, 2017 report from Bloomberg News. In September 2019, he acquired the remaining 51% of the Nets and took full ownership of the Barclay Centre. Tsai paid $3.4 billion for both stakes and the stadium, according to a New York Post report. In June 2024, he sold 15% stake to Julia Koch for $688 million in cash, according to Sportico. The franchise is valued at $6.22 billion, based on an October 2025 analysis by valuation consultant Sportico.
The value of the liabilities is based on an analysis of dividends, insider transactions, taxes and market performance.
Rachel Chan, a spokeswoman for Alibaba, declined to comment on Tsai's wealth.
Joseph Tsai was born in Taipei in January 1964 to a corporate lawyer and his wife. He was sent by his parents at age 13 to Lawrenceville School, one of the most expensive boarding academies in the U.S. where he learned to play lacrosse. He graduated from Yale University with a bachelor's degree in East Asian studies and economics in 1986 and continued his education at Yale to study law.
Tsai took a job in New York as a tax associate at the lawfirm Sullivan & Cromwell. He joined the buyout firm Rosecliff as vice president and general counsel, then moved to Hong Kong as a private equity investment manager for Investor AB, the Stockholm-based holding company controlled by the Wallenberg family. He married Clara Wu in 1996.
Three years later, he was introduced to Jack Ma, the founder of Alibaba.com, through a friend in Taiwan. Ma, who was running the startup from his Hangzhou, China, apartment without any financial or legal background, offered Tsai a salary of $50 a month -- a far cry from the $700,000 he was earning at Investor AB.
To Ma's surprise, Tsai took the job even though his wife was pregnant, By 2000, he was negotiating with investors, including SoftBank, Goldman Sachs and Fidelity Investments. He raised $25 million.
In later years, Tsai led efforts to establish Alibaba's headquarters in Hong Kong, list the shares in Hong Kong, and negotiate with Yahoo as a strategic investor. He's was in charge of Alibaba's initial public offering, the biggest in U.S. history. In addition to Alibaba.com, an online B2B e-commerce website, the company operates Taobao, China's top retail site, and Alipay.com, the country's most popular online-payment service.