U. S. Attorney for the Southern district of N.Y. Preet Bharara speaks at a news conference, Tuesday, Nov. 20, 2012, in New York. Mathew Martoma, a former hedge fund portfolio manager was arrested Tuesday on charges that he helped carry out the most lucrative insider trading scheme in U.S. history, enabling investment advisers and their hedge funds to make more than $276 million in illegal profits. (AP Photo/Louis Lanzano)

U. S. Attorney for the Southern district of N.Y. Preet Bharara speaks at a news conference, Tuesday, Nov. 20, 2012, in New York. Mathew Martoma, a former hedge fund portfolio manager was arrested Tuesday on charges that he helped carry out the most lucrative insider trading scheme in U.S. history, enabling investment advisers and their hedge funds to make more than $276 million in illegal profits. (AP Photo/Louis Lanzano)

U. S. Attorney for the Southern district of N.Y. Preet Bharara speaks at a news conference, Tuesday, Nov. 20, 2012, in New York. Mathew Martoma, a former hedge fund portfolio manager was arrested Tuesday on charges that he helped carry out the most lucrative insider trading scheme in U.S. history, enabling investment advisers and their hedge funds to make more than $276 million in illegal profits. (AP Photo/Louis Lanzano)