Think a health care public option is just some communist plot to send all old people to death camps? Well, I have a barometer for you on just how important this option is to reduce costs on health care....The Stock Market.

While the broad market was slammed, shares of large health insurers rallied as the Obama administration apparently backed off its plan to give Americans the option of signing up for a government-run health-insurance option. See full story on prospects for a public option.

"Health care can outperform in a declining stock market, but what's going on today is that investors have a growing belief that a public plan will not be part of the final solution," said John Sullivan, director of research at Leerink Swann, a health-care investment bank.