I understand if a trader does not have the capital necessary to open their own Customer Portfolio Margin account (CPM) why they look for a prop firm. I don't understand why a trader with assets would benefit from the relationship. Your capital invested in a JBO is no longer âyourâ capital. It's an investment in a broker dealer as a Limited B partner. It is subject to all the downside risks of other traders, while not participating in their profitability.You are bound by all rules associated with the JBO Partnership.Managerial discretion may permit other traders to trade âlargerâ than their equity warrants, thus reducing other JBO tradersâ capacity to take on risk. Your capital is "locked up" for 365 days. The prop firm often takes a percentage of your trading profits, yet as an investor in the firm, you don't participate in their earnings. If you open your own CPM, you get a segregated customer account at a Prime Broker with SIPC protection. You can receive up to 6.67 to 1 haircut for leverage both during the day and at night. You can receive competitive rates and if your not happy with your rates or service, move your account without any lock up period. Your account, your trading, your business. Any questions?