Much has been made of health-insurance premiums rising under the Patient Protection and Affordable Care Act, also known as Obamacare. Yet although many states have indeed seen premium increases, others are expected to see extensive declines. A recent study from the Manhattan Institute looked at premiums across the country to figure out which states would end up seeing the biggest cost savings from Obamacare.

In the following video, Dan Caplinger, The Motley Fool's director of investment planning, looks at the results of the study and finds that in four states, premiums under the Affordable Care Act are slated to more fall by 20% or more. Dan runs through the four states, noting that in New York and Colorado, declines will be roughly equal across the board for those of all ages, especially with New York having stable rates statewide. Meanwhile, in Ohio, young men will pay more, but older residents will get the lion's share of the cost savings under the Affordable Care Act. In Massachusetts, middle-aged residents will save the most under Obamacare.

Dan goes on to discuss how these results generally reflect the high-quality insurance policies these states already made available to their residents. At the same time, he notes that health-insurance companies Humana (NYSE:HUM), WellPoint (NYSE:ANTM), and UnitedHealth Group (NYSE:UNH) could earn less revenue in these states because of the lower premiums. At the same time, though, Dan points out that other rules under Obamacare would have limited insurers' ability to generate profits beyond a certain point in any event.

Fool contributor Dan Caplinger has no position in any stocks mentioned. The Motley Fool recommends UnitedHealth Group and WellPoint and owns shares of WellPoint. Try any of our Foolish newsletter services free for 30 days. We Fools don't 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.