The number of PPACA enrollments is expected to grow significantly in the next open enrollment period. Technology firm Healthcare.com estimates that 12-16 million people will enroll in plans under PPACA in 2015, up from 8 million who enrolled in 2014.

HHS noted that about 88 percent of employees receiving coverage through the Federal Employee Health Benefits Program don't wish to change plans and are instead auto-enrolled in their current plan with updated premiums and benefits.

Consumers who are automatically re-enrolled in PPACA plans will still have the option of changing plans during open enrollment, which runs Nov. 15 through Feb. 15, according to the rule. Enrollees also can return to the system to report life changes.

Even if someone is no longer eligible for a subsidy, they will still be auto-enrolled in their current plan, just without a tax credit, HHS said. State-based exchanges may also take this approach, HHS said, or may propose an alternative.

Under the rule, “consumers in the federally-facilitated marketplace will receive notices from the Marketplace informing them how to update their information to get a tailored and updated tax credit that keeps up with any income changes,” HHS said in its press release. “Consumers will receive information from their health insurance company about the premium and the amount they are eligible to save on their monthly bill close to the beginning of the open enrollment period, when they will be able to take action should they choose to do so.”