The SEC is the primary agency that regulates insider trading, with statutory authority to bring administrative proceedings and cases in federal district courts to enforce insider trading regulations.  While the SEC generally takes the lead in regulating insider trading, it can and often does advise the DOJ of its insider trading investigations; the DOJ may bring criminal and, in certain cases, civil charges.  The SEC and DOJ may conduct parallel investigations, and it is not unusual for SEC civil charges to be filed on the same day as the DOJ announces a criminal indictment in the same matter.