Susquehanna Investment Group, one of the largest quantitative trading firms in the world, just filed a lawsuit in Manhattan federal court against 100 people it can’t name yet. The Pennsylvania-based firm alleges those unnamed individuals collectively pocketed more than $100 million by trading on insider knowledge about China’s crackdown on cross-border brokerages.
Susquehanna says it was on the losing end of those trades. The firm claims losses exceeding $70 million, having served as the primary market-making counterparty for the positions in question.
What happened
The lawsuit, filed on June 29, names 100 “John Doe” defendants, a legal mechanism used when a plaintiff knows wrongdoing occurred but hasn’t yet identified who did it.
At the center of the case is a Chinese government crackdown on cross-border brokerages that took place in May 2026. Cross-border brokerages are firms that facilitate trading between Chinese investors and foreign markets, a space that has long operated in a regulatory gray zone.
