First, the administration released proposed regulations regarding reenrollment for 2015. As some expected, the regulations confirmed that insurance exchanges would reenroll individuals in their existing plans if enrollees remain eligible for qualified health plans through the exchange and the plan in which they were enrolled remains available for renewal.

The same day, consultants at Avalere Health released an analysis showing that most low-cost plans have proposed sizable rate increases for 2015. In seven of the nine states Avalere analyzed, the lowest-cost “silver” plan would change; in six of the nine states, the second-lowest-cost silver plan would change.

These pricing changes have special importance: Federal insurance subsidies are tied to the price of the second-lowest-cost silver plan. Enrollees in plans with premiums greater than that benchmark stand to pay the full difference in premiums–without additional federal subsidies. The Avalere analysis demonstrates how costly such a decision could be. One hypothetical enrollee in Maryland would see her out-of-pocket premiums rise from $58 per month to $94, a 62 percent increase. In this instance, $32 of the $36 monthly premium increase stems from staying in a plan more costly than Maryland’s benchmark premium.

The administration no doubt views auto-enrollment as a way to minimize what even a supporter of the health-care law called the “massive technological challenge” associated with redetermining eligibility. But as The Wall Street Journal reported two weeks ago, the lowest-cost plans for 2014 have recorded some of the highest enrollments this year—and have proposed large increases for 2015. Unless millions of individuals switch plans, they could be in for some nasty spikes in their out-of-pocket premium costs come Jan. 1.

This post was originally published at the Wall Street Journal Think Tank blog.