There are a number of reasons why IBKR shares are cheaper than most other brokerages. For one, the company is much smaller than its competitors. This gives it less buying power and limits its ability to offer certain services. Additionally, IBKR is a discount broker that doesn't provide the same level of research and analysis as full-service firms. Finally, the company's business model is focused on providing low-cost trading for active investors, which puts it at a lower price point than many other brokers.