The subpoena is the second that federal prosecutors have served on the investor, who also served as an unpaid adviser to the Trump administration.
The broker, Trevor Rahn, was discharged about three months after a settlement over a customer’s complaint that he had made improper trades.
Citigroup had said it was offering a safe haven from high-frequency traders. A Wall Street regulator says the company failed to keep its promise.
A recent revision to an opinion in an insider trading case could make prosecutors’ jobs easier in the case against the congressman from upstate New York.
President Donald Trump is declaring that "Tariffs are the greatest!" and threatening to impose additional penalties on U.S. trading partners he prepares for negotiations with European officials at the White House
The Supreme Court opened the door to legalized sports wagering. Sports teams, leagues and casinos are all looking to cash in. Yet the biggest winner might be hackers.
Regulators charged a second former Equifax worker, accusing him of buying stock options before the breach of 140 million consumers’ data became public.
The San Francisco-based investment banker and a friend from Seoul shared a brokerage account where they made illegal trades, federal prosecutors said.