Interactive Brokers Group, Inc. (NASDAQ:IBKR) reported its second-quarter financial results Tuesday after the closing bell. Here's a look at the key figures from the report.  The Details: Interactive Brokers reported quarterly sales of $1.29 billion which beat the analyst consensus estimate of $1.262 billion by 2.21% and represents a 29% increase over sales of $1 billion from the same period last year. The company reported quarterly earnings of $1.76 per share, which beat the analyst consensus estimate of $1.74 by 1.15%. Customer accounts increased 28% to 2.92 million and customer equity increased 36% to $497.2 billion. Commission revenue increased 26% ...