The unexpectedly close attention consumers are paying to prices on marketplaces created by the Affordable Care Act is contributing to millions of losses at Humana and merger partner Aetna, leading both insurance giants to retreat as fewer healthy people than forecast have signed up, according to a new story by The New York Times.

The result: Louisville-based Humana said it plans to largely exit the marketplaces, reducing coverage to no more than 156 counties in 2017 vs. 1,351 today.

Aetna of Hartford expects a loss of more than $300 million in Affordable Care Act business this year; it previously said it was a break-even operation. And it told investors in its second-quarter financial report that it’s halted plans to enter more states. “We are evaluating our footprint as it exists today to understand what solutions we can put forward to either fix the business or exit the business,” CEO Mark Bertolini told Wall Street analysts.