The U.S. Department of Justice has urged the U.S. Securities and Exchange Commission and the U.S. Commodity Futures Trading Commission to make over-the-counter derivatives rules tougher than those being proposed by the agencies. In separate comment papers to each commission, Christine Varney, head of the DOJ’s Antitrust Division, wrote that the proposals don’t go far enough in limiting the aggregate percentage that individual derivatives dealers can own of securities-based swap executive facilities and national securities exchanges.