The performance of the Interactive Brokers Group IBKR stock has been impressive this year. Its shares have rallied 47.2%, outperforming the industry’s 38.5% growth and the S&P 500 Index’s 19.7% rise.

Interactive Brokers' stock has soared, fueled by surging account growth and strong momentum across its entire business.

Interactive Brokers is a fast-growing brokerage service that professionals love to use. Its fast customer growth has led to impressive earnings growth for the stock. Even though the stock has soared, ...