Aetna Inc., citing losses of at least $300 million this year on Affordable Care Act (ACA) health insurance policies, announced it is abandoning the Obamacare marketplaces in 11 of the 15 states it currently serves, leaving Pinal County in Arizona with no insurer willing to offer policies.

After the move, Aetna will be offering policies in just 242 of the 778 counties it currently serves, and then only in four states: Delaware, Iowa, Nebraska and Virginia.

If no insurer steps up to offer policies in Pinal County, near Phoenix, residents there will be unable to get subsidies from the federal government for their policies. Subsidies are available only to individuals who purchase health insurance on the Obamacare exchanges.

The five largest national health insurance companies have all reported financial losses on exchange policies this year. Other insurers, focusing largely on Medicaid plans, report doing well.