A federal judge ruled against Susquehanna International Group's lawsuit alleging insider trading caused $70 million in losses from a Chinese regulatory crackdown, denying a request to keep alleged traders' accounts frozen. US District Judge Arun Subramanian said Susquehanna failed to identify an alleged 'tipper' and noted other explanations existed for the trades. Susquehanna sued 100 John Doe defendants in Manhattan federal court in late June, claiming insider trading on a May 22 Chinese government announcement targeting cross-border brokerages.

The firm argued such trading explained the option bets, while Citadel Securities joined the suit citing similar losses. Subramanian previously granted freezes on Interactive Brokers Group Inc., Futu Holdings Ltd., and Up Fintech Holding Ltd. accounts. Some John Does identified themselves, arguing their trades weren't based on inside information.

The judge noted algorithmic trading, AI agents, and career traders using analyst information, market trends, and forum 'scuttlebutt' for split-second decisions. Susquehanna and Citadel Securities now seek a narrower freeze on 45 traders' accounts after dropping claims against dozens of others.