Dantchik is a co-founder of Susquehanna International Group, a proprietary trading firm. The Bala Cynwyd, Pennsylvania-based company makes markets in financial products and asset classes with a focus on derivatives. Dantchik also has a minority stake in ByteDance, the developer of TikTok, and sits on its board.
Dantchik's fortune is derived from Susquehanna International Group, a market-making and proprietary trading firm he co-founded. He's credited with 19% of the firm, based on a June 2022 report in ProPublica.
Susquehanna's 2025 revenue is calculated at $22.1 billion based on having about 3,500 employees and the average revenue-to-employee multiple of a basket of other trading firms. Its calculated to have the same Ebitda margin as Jane Street in 2025, roughly 67%, and the same level of debt-to-employee. The business is valued using the average enterprise value-to-Sales, enterprise-to-value-to-Ebitda and price-to-earnings multiples of publicly-traded peers.
Susquehanna also owns about 15% of ByteDance based on an October 2020 Wall Street Journal report and adjustments for dilution. Dantchik is credited with 19% of that stake based on his Susquehanna ownership.
It's valued at $435 billion in this analysis based on the average of investors BlackRock, T. Rowe and Fidelity valuations as of December 2025, as well as a $420 billion stake sale in November 2025, according to a Bloomberg News report.
Bytedance completed a sale of TikTok US in January 2026. Susquehanna owned about a quarter of the roughly 60% stake in Bytedance owned by foreign investors, and its credited with the same percentage of the 30% stake in TikTok US owned by existing Bytedance investors following the deal. About 19% of that, or about 1.4%, is credited to Yass. Its valued using the sale value of $14 billion.
A spokesperson for Dantchik didn't respond to a request for comment on his wealth in March 2026.
Arthur Dantchik was raised in New York City and attended Bayside High School in Queens, where he met Jeff Yass.
The two roomed together at the State University of New York and both enjoyed poker and horse racing. After graduating the two moved together to Las Vegas where they gambled professionally.
In 1987 Yass, Dantchik and four of their college friends founded Susquehanna International Group. The firm began as an options market-maker before becoming a trader in a wide variety of financial asset classes.
Dantchik was responsible for setting up Susquehanna's venture capital arm, which made a very successful investment in ByteDance, the developer of TikTok, in 2012. Dantchik subsequently joined the company's board.