The New York Times reported that two of the four arrested Tuesday, Donald Longueuil and Noah Freeman, worked previously at SAC Capital Advisors.
Samir Barai of the hedge fund Barai Capital Management was also arrested Tuesday, as was Jason Pflaum, previously an employee at Barai's firm.
Pflaum is said to be a cooperating witness in the case that stems from a long-running investigation with part of the evidence collected by FBI wiretaps, the Times said.
Arguably, the most prominent money manager involved in the case is billionaire Raj Rajaratnam, a co-founder of the hedge fund Galleon Group.
Rajaratnam, arrested in October 2009, is contesting the charges against him. His trial is scheduled to start Feb. 28 in Manhattan.