I make money selling covered calls on FX spot options, and some of my friends want to buy in to this without having to trade their own accounts.
One method is for each of them to get an account, and have me trade it, but that doesn't scale well: I really don't want to be trading 10 accounts.
The other method is to let them "buy in" to my account. My question: how do I determine what "portion" of my account someone owns, assuming many people (including myself) deposit and withdraw money?
Is there a better way of doing this? What if I charge my friends a small fee to trade?
I'm guessing the answer is well known, since hedge funds/mutual funds have to deal with this all the time.