Will the old adage of what goes up must come down apply to the stock markets this year?

2016 was a great year for stock markets. However, many investors are worrying that the old adage of what goes up must come down may apply in 2017 with some commentators speculating that the markets may indeed be overvalued. For more on this, Share Radio's Ed Bowsher spoke to Dan Kemp, Chief Investment Officer at Morningstar, the investment research and investment management firm. They began by examining what was behind the bumper year enjoyed by many of the world's stockmarkets.