Key Points UnitedHealth Group (NYSE: UNH) is the top dog in health insurance in America, recently with a market value of $313 billion. Its stock is down some 37% over the past year, though, for several reasons, such as its being investigated by the Department of Justice for possible Medicare fraud, and its CEO having stepped down. With the stock down so much, that means its dividend yield has been pushed up -- recently to 2.5%. (Add in stock buybacks, and shareholders have recently been rewarded with a tota ...