IBKR 10-K Analysis: The Rate-Cut Paradox Hiding a $650M Earnings Floor
Interactive Brokers grew revenue 20% to $6.2 billion with a 77% pretax margin — but this isn't really a trading platform. The 10-K reveals 57% of revenue is net interest income, and rate cuts paradoxically helped: NII grew 13% despite 27bps of margin compression because $29.6B in balance growth overwhelmed the rate impact. A structural 0.50% spread floor creates a ~$650M NII minimum. Meanwhile, 76% of net income flows to the Peterffy family through the LLC structure — public shareholders get 24% of a financial machine with zero debt and $203B in liquid assets.