Our main accounts are with Schwab in the USA, and I consider the risk of broker failure to be so close to zero that it cannot be expressed mathematically. For an account with a value below the SPIC limit of $250K, there is no risk of loss to the customer. But brokers can get into other kinds of trouble LOL. During the initial COVID lockdown in 2020, customer service at Schwab went down the sewer. Most reps were working from home, but during the first couple months, many of them did not have access to the tools and resources they needed to address customer concerns. The hold times were outrageous. And of course, you couldn't walk into a retail Schwab office, because they were closed. Live chat and messaging were no better. Effective and efficient communication with the broker became almost impossible. At times, their phone system was so overloaded that it couldn't even process incoming calls. Menu options were not working. Some calls would ring into a black hole, with no answer, or a fast busy signal, or a wierd error message recording. That was when I decided we needed an account at a second broker. Of course, most of the other brokers were experiencing similar problems. It was just a matter of degree. But we opened an account at e*Trade, and we still have it today.