But one insurance expert said UnitedHealth's statements are evidence that the Obama administration needs to adjust the ACA if the program is to remain a viable option for both insurers and for customers.
"The Obamacare business model doesn't work," said Robert Laszewski, president of consultancy Health Policy and Strategy Associates in Virginia. "Obamacare has got to be retooled."
Laszewski cited the fact that insurers overall still are losing money selling exchange plans in the second year of Obamacare, and that as a result many of them are raising prices, which could in turn lead to current and prospective customers taking a pass on further coverage.
"Premiums after subsidies are still too high," he said, referring to the tax credits most exchange customers get to lower their monthly premium cost. "Deductibles are up the roof, networks [of health providers in plans] are narrowing."
"The pro-Obamacare people, including the administration and all of the supporters, have really talked themselves into the notion that Obamacare is well-designed and it's working," Laszewski said. "These people are in denial."
He called for the administration to loosen regulatory restrictions on the design of insurance plans so that insurers can offer customers coverage that is more affordable while still being attractive.
"Fundamentally, the carriers have to be allowed to sell health plans that people want to buy," Laszewksi said.
Clare Krusing, spokeswoman for the industry group America's Health Insurance Plans, said that UnitedHealth's comments Thursday reflect what members of AHIP have been experiencing themselves in recent months with their exchange products.
"This has been a very challenging market; it's still a market in transition," said Krusing.
Krusing said the announcement by the federal government that there would be a significant, $2.5 billion shortfall in the money that insurers could expect to get from Obamacare's so-called risk-corridor program has led to "tremendous uncertainty, tremendous instability" in the exchange market. The risk-corridor program is designed to help insurers deal financially with not getting enough in premium payments to offset their costs from paying out health benefits.