An unlikely winner in the long-running bull market: Health insurers

The S&P 500 is up well over 300 percent over the last nine years, but health insurance stocks have logged even more impressive gains. The S&P Managed Care sector, made up of the largest insurers, has gained more than 1,100 percent during the market's bull run. In March 2009, when the stock market hit bottom, health insurance stocks hardly seemed like a sure bet.