Market maker Susquehanna International Group has filed a federal lawsuit against 100 unidentified defendants, accusing them of insider trading. The firm alleges traders used non-public knowledge about a Chinese regulatory crackdown to pocket over $100 million in options profits, while Susquehanna absorbed more than $70 million in losses.
In the two weeks before May 22, 2026, traders purchased roughly $12 million in short-dated put options on shares of Futu Holdings and Up Fintech, the parent of Tiger Brokers. These aggressive bets predict a stock's price will fall.
On May 22, Beijing announced a crackdown on unlicensed cross-border securities services. Futu was fined 1.85 billion yuan, about $272 million. The share prices of both companies plunged, and the put options soared in value to over $100 million, a return exceeding 900%.
The lawsuit, filed in Manhattan federal court, targets "John Doe" defendants. The court has authorized subpoenas to several brokerages, including Interactive Brokers, Futu, and Tiger Brokers. Both the Department of Justice and the Securities and Exchange Commission have reportedly launched investigations.
The case underscores a vulnerability for market makers, who price options based on public information and face massive losses when material non-public information triggers a market event. For investors in US-listed Chinese financial firms, the significant fine signals Beijing's continued focus on tightening oversight of cross-border financial services.