According to Warren Buffett's math the stock market is officially in "playing with fire" territory. So when is the next crash coming?

Warren Buffett has long held to a simple maxim when it comes to whether the stock market is undervalued, fairly valued, or overvalued. His thesis: The total value of U.S. stocks, over the long term, can’t outpace the growth of businesses as reflected in the GDP. So when the ratio of S&P 500 to natio