Interactive Brokers is a large, automated retail and institutional brokerage that boasted nearly $780 billion in customer equity at the end of 2025. The company cut its teeth as a market maker, introducing US financial markets to automated and algorithmic training before expanding into brokerage services in 1993. The firm has a wide-ranging client base, with its best-in-class order execution and extremely low margin lending rates catering to a sophisticated audience of hedge funds, proprietary traders, and introducing brokers that account for about 45% of the firm's commissions. With operations spanning more than 170 electronic exchanges, 40 countries, and 29 currencies, Interactive Brokers caters to a global clientele, with more than 80% of client accounts sitting outside the US.