Up 18% Already in 2026, Is it Too Late to Buy Interactive Brokers Stock?

Core Insights - Interactive Brokers has demonstrated impressive growth in 2025, adding over 1 million net new accounts and increasing client equity by 37% year over year to $780 billion, a $200 billion increase [1] - The stock has risen approximately 46% in 2025 and an additional 18% in 2026, with a remarkable 340% increase over the past five years, raising questions about its current valuation [2] Financial Performance - The fourth-quarter revenue for Interactive Brokers increased by 21% year over year, driven by a 22% rise in commission revenue and a 20% boost in net interest income [3] - Net interest income was the primary revenue driver, contributing $966 million to the total revenue of $1.64 billion during the quarter, while commission revenue accounted for $582 million [4] Customer Growth and Trading Activity - The company experienced significant growth in customer trading volume, with year-over-year increases of 27% in options, 22% in futures, and 16% in stocks, alongside a 32% rise in customer accounts to 4.4 million [5] - Non-GAAP earnings per share saw a 27% year-over-year increase, highlighting the effectiveness of the company's automated global platform [6][7]