GREENWICH, Conn.--(BUSINESS WIRE)---- IBKR #IBKR--Interactive Brokers Group, Inc. (Nasdaq: IBKR) an automated global electronic broker, today reported its Electronic Brokerage monthly performance metrics for December. Brokerage highlights for the month included: 3.384 million Daily Average Revenue Trades (DARTs)1, 4% higher than prior year and 21% lower than prior month. Ending client equity of 779.9 billion, 37% higher than prior year and 1% higher than prior month. Ending client margin loan balances of ...