Interactive Brokers is more than a bet on trading volume.

In Q3, net interest income was $1.154B, versus $602M in commissions. Interest supplied 60.3% of net revenues, up from $967M a year earlier.

More client balances and borrowing can expand earnings alongside trading. But that also makes rates and funding costs part of the investment case.

A growing account count isn't enough if revenue per balance compresses. Compare net interest income with average client balances, not just trade counts.

This is a revenue mix, not a profit split or proof the stock is cheap.