The FBI is investigating high-speed trading firms to determine whether they are engaged in insider trading, the Wall Street Journal reports.
The investigation was launched a year ago but remains in the early stages.
Among the focuses is whether high-speed investors are trading using information that others can’t access.
Investigators also are investigating a type of trading in which investors create the false appearance of market activity by placing a group of trades and then canceling them.
“There are many people in government who are very focused on this and who are concerned about it and who think it breaks the law,” an FBI spokesman said. “There is a big concern that high-frequency traders are getting material nonpublic information ahead of others and trading on it.”