Wall Street is bracing for more volatility in the stock market next year, and some strategists even suspect that we're not far from the end of this bull market. Against this backdrop, a comparativey safe asset class that has underperformed the stock market for most of the post-crisis period is suddenly regaining its allure. According to Goldman Sachs, investor holdings of this asset are at the lowest levels in 30 years. King Cash is making a grand comeback.