RedSun - A Prop firm is a trading operation that can be either regulated or unregulated. An unregulated prop firm uses partner's capital to make money by trading. They can hire employees to trade, but they are employees. They can't take trader money as first loss and mark up anything for profit. They make their money when the trader makes money trading. The regulated prop firms come in general in two types and are SEC regulated Broker Dealer and require a SRO to monitor their business like an exchange or FINRA. They are the traditional prop firm and JBO. An example of the traditional prop firm would be SIG (Susquehanna Financial Group). They make their money when the trader makes money trading. They traders are employees and do not offer capital. The other type is the Joint Back Office (JBO) structed Prop Firm. This is the type where the trader puts up money as first loss, the firm provides leverage, the trader is some type of partner and get paid with a K1. This model allows the firm to markup commissions, interest, platform fees etc. They can make their money from education, commissions, interest, desk fees, and their cut of profits, which is generally very low and not a profit center. These firm require you to lock up your deposit for 1 year and follow their rules, if your capital is commingled with firm capital, which is the most common set up. I hope this helps. Feel free to contact me directly for any follow up questions.