Cigna's bet? So many aging baby boomers will need Medicare in the coming years that whatever Washington cuts in funding will be made up in sheer volume.
A brief review: Medicare provides government-administered insurance to the elderly and the disabled. Funded through payroll taxes, Medicare pays 80 percent of most hospital and doctor bills.
Consumers either buy supplemental "Medigap" insurance or a Medicare Advantage plan, which picks up the balance of the costs and offers other services, including pharmaceutical, care coordination, wellness, and vision, depending on the plan.
In Medicare Advantage plans, the government pays the insurance company what it would have paid for health expenses, plus additional payments to administer the plan and provide additional services.
Now, virtually all the additional payments have been eliminated - a process that began in the administration of President George W. Bush, and accelerated as a way to fund the Affordable Care Act passed in 2010. The cutting continues as part of the efforts to reduce the budget deficit.
So why would Cigna make this bet? Besides the demographics, it also amounts to a hedge on uncertainty, said health economist Mark V. Pauly of the University of Pennsylvania's Wharton School.
"When you talk about insurance these days, misery is all relative," he said.
No one is quite sure yet, he said, how the Affordable Care Act will impact the private insurance market - so for Cigna, which traditionally has focused on selling insurance to large companies, a major move into government insurance also represents a bit of a safety net.
Cigna, which until recently was headquartered in Philadelphia, did not have much Medicare business.
