Stephen Maturen / Getty Images UnitedHealth Group (UNH) stock had one of its worst days ... In defensive sectors like health care and consumer staples, companies usually lose that kind of market ...

Stephen Maturen / Getty Images Shares of UnitedHealth Group (UNH) finished more than 22% lower Thursday in the stock's worst day in over 25 years after the health-care giant's first-quarter ...

Its stock price fell 6 percent, a tough day on Wall Street for the largest private health insurer in the United States ... point about the American health care industry. That signal is ...