Thursday is the last day to sign up for health care coverage through the Affordable Care Act. Above, Secretary of Health and Human Services Sylvia Mathews Burwell spoke during a press conference on Open Enrollment in Washington, Feb. 18, 2015. Reuters/Yuri Gripas

For people who were unpleasantly surprised earlier this month by tax penalties for not having health insurance, there may be comfort in knowing they have one last day to avoid a higher fine next year, as the sign-up period for health care coverage under the Affordable Care Act ends Thursday.

The deadline to sign up for coverage through the federal exchange and state marketplaces was originally Feb. 15 but was extended shortly thereafter. The federal government said it would give consumers until April 30, two weeks after taxes were due, to sign up. Most states granted residents the same extension, though others, like Washington, gave less slightly time. Colorado, Idaho and Massachusetts granted no extension at all, while Vermont has given its residents until May 31 to buy coverage, according to Enroll America.

In order to qualify for what is referred to as a Special Enrollment Period, consumers had to attest they did not know they would be required to pay a tax penalty for lacking health insurance. Many discovered when filing their taxes for 2014 that they would be fined $95 per person or 1 percent of their income -- whichever was higher -- for not having coverage last year.

That fine is slated to rise to $325 per person or 2 percent of income, whichever is higher, in 2015, and will be even more in 2016. The fine, a key component of the Affordable Care Act’s individual mandate requiring everyone to have health care coverage, was intended to spur people to buy insurance, although whether it has actually worked is subject to debate. Nevertheless, the strategic extension of the deadline to April 30 reflects the hope that people would be inspired to buy insurance after learning, at the latest by April 15, about the tax penalty.

“Owe the fee for not having 2014 coverage?” asks the website for the federal exchange, HealthCare.gov. “You can still get 2015 health care coverage,” a banner at the top of the site, which people can visit in order to sign up for coverage, reads.

According to ACASignups.net, which tracks enrollment through the Affordable Care Act, some 11.9 million people had signed up for health insurance of April 28. After the original deadline of Feb. 15 passed, an estimated 11.4 million had enrolled in plans.