Prime brokers make money by charging a fee or commission for facilitating the transactions for the funds that they manage. This fee is normally called a “spread”. Publically traded online trading platforms like IG, CMC Markets, City Index (owned by StoneX) and Interactive Brokers are generally safer as they must report their financial status to the stock exchange and investors more frequently than private companies. By keeping an eye on a company’s share price you can see how healthy its balance sheet is. There is no guarantee that any trading platform will not go bankrupt, but there are ways to keep an eye on the health of the company behind it. Funds up to £85k are predicted by the FSCS if a broker defaults, but not above that amount, unless insurance is in place.