As banks have begun winding down their in-house trading desks to comply with the rule, many traders have headed to places like Citadel. But the trend was under way well before Dodd Frank and will surely continue for one big reason: The moneymaking possibilities at hedge funds are much, much greater than they are almost anywhere else. As the largest hedge funds have become multibillion-dollar investment behemoths with high fixed fees, the potential for enormous fortunes to be made has increased exponentially -- even, in some cases, when the fund's performance isn't so great. Suddenly, the prospect of making millions at a big bank might not seem terribly attractive to a trader, compared with the prospect of hundreds of millions at a hedge fund.