Regulators in the United States are investigating allegations raised by Susquehanna International Group involving alleged insider trading ahead of a Chinese regulatory crackdown on cross-border brokerages. Bloomberg and the Financial Post report that the Securities and Exchange Commission is probing the matter after Susquehanna claimed that unnamed insiders placed options bets that generated more than $100 million in profits. Separately, the Justice Department is also looking into similar allegations, according to people familiar with the matter. The reports describe the disputed trades as options positions taken before the crackdown, but they do not name specific individuals or entities accused of providing or using material nonpublic information. Separately, Citadel Securities asked to join a lawsuit tied to the same alleged scheme, saying it was a victim of the conduct that Susquehanna described. Citadel’s request indicates broader litigation beyond Susquehanna, though the details of claims and parties involved in court filings were not provided in the excerpts. The investigations and legal action appear to focus on whether trading around the announced regulatory event involved unlawful use of information.