Interactive Brokers: Margin Loans Up 67%, Interest Margin Down to 1.93%

FM Intelligence examines how Interactive Brokers Group's Q2 2026 growth shifted from trading activity toward balance-sheet expansion, why net interest margin has fallen year-over-year for six consecutive quarters, and what three interest-rate paths imply for net interest income through 2027.

Interactive Brokers Group, Inc. reported Q2 2026 net revenue of $1.90 billion, up 28% year-over-year, and net interest income of $1.06 billion, up 23%. Customer margin loans reached $108.5 billion, up 67%, outpacing both the 34% rise in customer accounts, to 5.19 million, and the 40% rise in customer equity, to $930.3 billion. Net interest margin fell to 1.93% from 2.07%, a sixth consecutive year-over-year decline, as the annualized yield on margin loans dropped to 4.10% from 4.67%. The increase in net interest income came from larger balances rather than higher rates. Pretax margin held at 77%, while customer bad-debt expense rose to $10 million from $1 million.