buy stocks on margin, or borrow against the equity in your home or 401k and invest the borrowed cash in the stock market. Just as with real estate, leverage increases the risk that things could go very badly — but it also opens the door to greater returns.

Personally, I don't recommend that investors borrow to invest in either stocks or real estate, other than one's primary residence (and not an excessive one at that), but I recognize that many real estate investors ignore this advice and for some reason think that leverage is unique to real estate.