In spite of their opposition to "Obamacare," health insurance firms such as WLP, UNH, and AET...

In spite of their opposition to "Obamacare," health insurance firms such as WLP, UNH, and AET have performed well since 2010's reform bill was passed: a Bloomberg study estimates the insurers' average operating margin rose to 8.24% in the 6 quarters since the bill became law, compared with 6.88% in the 18 months prior to its passage. Rising Medicare and Medicaid revenues are behind the surge.