It would be a bit too much hyperbole to say that 2016 was an incredible year for the stock market. Still, the S&P 500‘s total return of 12.25% over the past year is nothing to shake a stick at. To some investors, the last several years of strong gains in the market, coupled with a inordinately high valuation across the board — the cyclically adjusted price-to-earnings ratio for the S&P 500 Index stands at 26.1 — suggest that there may not be a whole lot of gains left to be had.