US prosecutors and regulators have broken up afamily-run insider trading ring that they say netted $3.7m over five years by trading on secret information gleaned at their jobs.

Zvi Rosenthal, his sons Amir and Ayal, and David Heyman, a family friend, pleaded guilty in federal court in Brooklyn yesterday to conspiracy to commit securities fraud. They each face up to five years in prison and $250,000 in fines when they are sentenced on May 18.