No change has hit the health care sector recently like Obamacare. The new health law has transformed many parts of America's insurance landscape, but one thing's remained the same: UnitedHealth Group's (NYSE:UNH) the market's largest insurer by subscribers. The blue-chip stock has surged over the past three months and delighted investors, but is UnitedHealth a good pick for your portfolio in the long run?

The company has done a good job keeping subscriber growth on course, but UnitedHealth has also helped draw down costs recently. The company's medical loss ratio -- its percentage of premiums going to cover medical expenses -- has fallen, while revenue has continued to surge. It's a combination that makes investors drawn to UnitedHealth's dividend, one of the best in the insurance market, smile.

But can UnitedHealth keep up its good start to 2014 over the long haul? Find out in the video below, as Motley Fool contributor Dan Carroll takes you through the biggest three reasons you should believe in this top health insurance stock -- and why UnitedHealth looks like a great pick in the long run.

Dan Carroll has no position in any stocks mentioned. The Motley Fool recommends Gilead Sciences, UnitedHealth Group, and WellPoint. The Motley Fool owns shares of Gilead Sciences and WellPoint. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.