With the Dow Jones Industrial Average (DJINDICES:^DJI) crossing the 15,000-point threshold for the first time recently, many investors and analysts are beginning to question whether equities are overvalued. Hedge fund managers have identified the Federal Reserve's third round of quantitative easing as the culprit, while others have cited rising margin debt as evidence. In the video below, Motley Fool contributor John Maxfield discusses whether it's reasonable to conclude that stocks are indeed overvalued and, if so, what investors should do about it.