People who were "in line" to enroll in Obamacare insurance plans as of this past Monday's deadline, but were unable to finish their applications because of technical problems on the federal exchange HealthCare.gov, will need to complete their enrollment by April 15—the same day as the dreaded income tax filing deadline.
The federal government last week said it would grant a grace period to people who ran into trouble finishing their enrollments on HealthCare.gov after starting the application process. But until Wednesday, officials had not disclosed how long that extension, the latest in a series of deadline shifts, would last.
"For those in line on the 31st [of March], we encourage consumers to finish the process as soon as possible. They must complete their enrollment by no later than the 15th [of April] for coverage this year," said Aaron Albright, spokesman for the Centers for Medicare and Medicaid Services.
The new deadline only applies to people who were electronically in line to enroll on HealthCare.gov, which sells insurance in 36 states. Nearly all other states and the District of Columbia have granted comparable extensions in similar cases, for varying lengths of time.
If those people don't finish their enrollment by the cutoff, they will be unable to sign up for Obamacare plans this year. That means they could face fines of up to 1 percent of their taxable income next year, for failing to have insurance.
It is not known how many people were in line on the federal exchange when the deadline came at midnight on Monday. But earlier that day, HealthCare.gov was on two different occasions unable to handle new applications and enrollments because of software issues, and a flood of people trying to beat the deadline.
To qualify for the grace period, people must attest they were in line at the time of the deadline, but were prevented from completing their formal selection of an insurance plan.
President Barack Obama announced Tuesday that 7.1 million people had enrolled for insurance by the original Monday deadline via HealthCare.gov, and via the exchanges run by the other states and the District of Columbia. The figure just beat the government's original estimates for enrollment by that time, and the grace period granted by the federal exchange and some others will boost that tally.
The exchanges, which launched in October, are selling insurance and helping people enroll in government-run Medicaid and the Children's Health Insurance Program [CHIP], as part of the Affordable Care Act's requirement that nearly all Americans have some kind of health-care coverage by this past Monday.
Although Monday was the deadline for open enrollment in private insurance plans effective this year, the exchanges will continue selling such plans to people who experience so-called qualifying life events, which include moving to a new state, getting married or divorced, and having a child.
That window for enrollments could increase the total tally for people with coverage this year. But down the road, that number will also be impacted by people who enrolled by Monday's deadline and will either not pay their first premiums, or will later drop out of coverage for a variety of reasons.
—By CNBC's Dan Mangan.