Don't assume that a fund called the "XYZ Stock Fund" invests only in stocks or that the "Martian High-Yield Fund" invests only in the securities of companies headquartered on the planet Mars. The SEC requires that any mutual fund with a name suggesting that it focuses on a particular type of investment must invest at least 80% of its assets in the type of investment suggested by its name. But funds can still invest up to one-fifth of their holdings in other types of securities — including securities that you might consider too risky or perhaps not aggressive enough.