@RealSeanBrodrick: I wager some of them figured they could rein it in so it would be more "serious" and/or "reputable", but my money is on most of them almost certainly didn't want to "miss the boat". Also, it was other people's money. Wall Street figured it'd collect fees and bonuses and such, and if things fell apart it wouldn't be on them. "Too Big To Fail" and all that. That philosophy's worked so well and profitably before.