Last November, when UnitedHealth Group said itexpected to post big losses on its Obamacare policies in 2016,rivals such as Anthem and Aetna signaled their Affordable Care Actbusinesses were doing fine. The Obama administration used that asevidence to refute claims that systemic problems were brewing inits landmark insurance program.

Now, there’s no denying it. The four biggest U.S. healthinsurers admit they’re each losing hundreds of millions of dollarson their Obamacare plans. Rather than expand coverage, many are pulling out of theexchanges that were set up by the ACA so people canshop for insurance plans, often with the help of governmentsubsidies.

UnitedHealth expects to lose $850 million on Obamacare in 2016,while Aetna, Anthem, and Humana are all on track to lose at least$300 million each on their ACA plans this year, according tocompany reports and estimates from Bloomberg Intelligence.UnitedHealth says it’s quitting 31 of the 34 states where it sellsACA policies. Humana is exiting 8 of 19 states and reducing itspresence to just 156 counties, from 1,351 a year ago. Anthem hasn’tannounced plans to change its participation in the program.