Have stock prices raced ahead of reality? Maybe not

As the stock market powers ahead again, many nervous investors are asking themselves if shares are now overvalued. The Dow Jones and the broader S&P 500, after all, are now up more than 50% off their recent lows and picked up again this week.

For many bears caught off-guard by the sharp upturn, like Gluskin Scheff analyst David Rosenberg, the answer is obvious: Stocks have again reached valuations not seen since the Internet bubble. But it's not that easy.