Susquehanna International Group (SIG) is a privately held quantitative trading firm that makes markets in listed derivatives, primarily equity and index options, using its own capital rather than managing money for outside clients. The firm provides continuous two-sided pricing and liquidity in roughly 600 equity options classes and around 45 index options products, and extends the same market-making approach into equities, ETFs, futures and fixed income; since 2024 it has added a dedicated desk trading event contracts on prediction-market venues. Its strategies are built in house by teams of traders, quantitative researchers and software engineers rather than licensed from outside vendors. SIG's main differentiator from competing options and ETF market makers such as Citadel Securities, Optiver, IMC and Jane Street is its recruiting and training culture, built directly on the founders' background as professional card players. New hires, mostly from quantitative and STEM backgrounds, are trained through structured poker and strategy games intended to teach probabilistic reasoning and decision making under uncertainty before they manage risk. As a proprietary trading firm it does not take client capital or offer investment advice in its core trading business; separate affiliated units, Susquehanna Growth Equity and Susquehanna Asia Venture Capital, run growth-equity and venture investing with outside limited partners, a different business model from the firm's market-making desks. The firm traces its start to a group of friends who met at SUNY Binghamton in the late 1970s, including Jeffrey Yass and Arthur Dantchik, and who began trading options independently on the floor of the Philadelphia Stock Exchange in the early 1980s before formally organizing as Susquehanna International Group in May 1987, naming it for the river near their college; the firm is reported to have earned about $30 million in revenue in its first year, aided by put option hedges it held into the October 1987 market crash. SIG is headquartered in Bala Cynwyd, Pennsylvania, and its own current site states more than 3,500 employees across 16-plus offices in North America, Europe and Asia Pacific; Wikipedia reports $7.2 billion in revenue for 2024. It is also known as one of the earliest outside investors in ByteDance, having put in roughly $5 million in 2012 in a stake later reported to be worth tens of billions of dollars, making it one of ByteDance's largest outside shareholders and a repeated subject of scrutiny in the US political debate over TikTok's ownership. In 2012, SIG was one of several broker-dealers, alongside Goldman Sachs and Bank of America, that paid a combined $18.5 million to settle a CalPERS-led class action alleging front-running of client orders. In April 2024, SIG became the first large institutional market maker to open a trading desk dedicated to event contracts on the exchange Kalshi, providing liquidity for six-figure trade sizes in political, economic and sports-outcome markets. It has since expanded that push, including an over-the-counter access partnership with crypto custodian BitGo, as regulated event-contract trading volume industry-wide grew from under $100 million a month in early 2024 to more than $8 billion by December 2025.
