Interactive Brokers earned $0.69 a diluted share, up from $0.51, as margin loans rose 67 percent

Interactive Brokers earned $0.69 a diluted share in the second quarter, up from $0.51 a year earlier, on net revenues of $1.90 billion, from $1.48 billion, for the quarter ended June 30. Income before income taxes was $1.46 billion, against $1.10 billion a year ago. The broker runs lean. Its pretax margin reached 77 percent, up from 75 percent, a level most financial firms do not approach and this one has held for years.

The engine was leverage. Customer margin loans increased 67 percent to $108.5 billion, and net interest income, the firm's largest revenue line, rose 23 percent to $1.06 billion. Customer accounts rose 34 percent to 5.19 million, and customer equity rose 40 percent to $930.3 billion. Commission revenue rose 30 percent to $673 million, with options volume up 17 percent and stock volume up 14 percent.

The board declared a quarterly dividend of $0.0875 a share, payable September 14. Interactive Brokers holds its equity in a basket of ten major currencies it calls the GLOBAL, and a 0.21 percent decline in that basket cut comprehensive earnings by $36 million in the quarter. Total equity stood at $22.3 billion.