So the likely hood of a start-up in investments, is pretty much out of reach. Was just thinking about how easy/hard it would be to take money from customers, i

So the likely hood of a start-up in investments, is pretty much out of reach. Was just thinking about how easy/hard it would be to take money from customers, invest it, and payout any profit. My friend has a guy who takes his money, and invests it for him (he's a private broker) - would this broker also need a team of lawyers? Or is he more of an accountant? In terms of everything else, I could give anyone $10k, and tell them to go across the street and buy mutual funds... with a written agreement to pay me the profits... couldn't I? Just trying to better understand...