There's some indication that they may make the insurance companies eat the shortfall, referred to in the article.
That though falls into the problem I outlined where insurance companies who participate extensively in the exchanges may go under, or withdraw after 2014 if they survive.
The insurance companies participating have 3 MAJOR problems right now.
1 - Too few enrollees, and of the wrong demographic
2 - The data they are getting from the exchange is wrong, requiring them to go get the data manually, increasing their costs
3 - Since the exchange set the wrong subsidized numbers, they may be on the hook for the difference
I think #3, if it occurs, will result in a bunch of major lawsuits. The Gov't cant really absolve itself of responsibility for providing incorrect information.
#1 kills them for obvious reasons - they're insuring un-insurables without an offset.
#2 kills them because they have to refund anything over 20% admin cost
#3 kills them because, frankly, they don't get paid
So this goes back to the big 3 insurers not participating in very many exchanges - Aetna, Cigna, and UnitedHealthCare.
They knew what they were doing.