I did this a few years ago. I opened an LP, and everyone who invested got a percentage in the LP. I only allowed contributions/withdrawals monthly, so if someone wanted in or out, it's easier to adjust everyone's % monthly, rather then in different time periods. I had a 1% mgmt fee, and 20% of profits. This is a basic Hedge fund profit sharing arrangement. At the end of the year I had a tax accountant issue K-1's to each of the partners.