Interactive Brokers Customers up 15x, Revenue Quadruples

Interactive Brokers reported a tenfold increase in share price over the past decade, turning a $10,000 investment into approximately $110,000 with dividends reinvested. This performance significantly outpaced the S&P 500, which grew a similar position to about $41,500 over the same period.

The brokerage’s compounded annual return of roughly 27% was fueled by a customer base that expanded nearly fifteen-fold and a strategic pivot to a higher-margin business model. As detailed in recent reporting by Yahoo Finance, the company shifted from a broad electronic broker to a leaner platform focused on net interest income and commission revenue.

Customer Growth Accelerates Significantly

Interactive Brokers ended August with 5.46 million customer accounts, a 35% increase year-over-year. This figure represents a nearly fifteen-fold expansion from the 370,000 accounts recorded at the end of September 2016. Notably, the growth rate has accelerated, rising from 32% in early 2025 to 35% by the third quarter.

The influx of customers brought substantial capital to the platform. Assets under management grew from $82.7 billion in September 2016 to $962.8 billion by the end of August 2025. This eleven-fold increase in client equity provides a stable foundation for the company’s interest-earning activities.

Revenue Model Shifts To Interest

Net interest income emerged as the primary revenue driver, exceeding $3.5 billion last year compared to $527 million in 2016. In the second quarter of this year, net interest income reached $1.06 billion, accounting for more than half of the company’s $1.9 billion in net revenues. This segment grew nearly seven times over the decade, outpacing other revenue streams.

The company’s strategic decision to exit the options market-making business in 2017 streamlined operations. By transferring its U.S. options market-making division to Two Sigma Securities, Interactive Brokers eliminated lower-margin activities. This structural change allowed the firm to focus on high-fee trading and interest income, boosting overall profitability.

Profit Margins Expand Substantially

Pre-tax profit margins improved from 55% in 2016 to 77% in the most recent quarter. Total net revenues more than quadrupled, rising from $1.4 billion in 2016 to $6.2 billion in 2025. This combination of volume growth and margin expansion resulted in significantly higher earnings per share.

Recent quarterly data indicates continued momentum, with commission revenue up 30% to $673 million in the second quarter. A Federal Reserve rate increase in September may further support net interest income. However, the one-time benefit of the margin expansion is already realized, and the stock’s valuation premium from 2016 remains high.