Americans currently receiving federal subsidies to help pay for their health care may get an unwelcome surprise this April, in form of a lower-than-expected tax refund.

The situation has arisen because the health care subsidy is technically a tax credit. When individuals originally applied for a subsidy, they provided their estimated 2014 income, which the IRS used in combination with other factors like family size, location, and the premiums for a ‘‘benchmark’’ plan in that locality to determine the amount of the tax credit issued.

But if someone ended up having a larger income in 2014 than initially anticipated, he or she may not end up qualifying for as much of a tax credit. And any difference will come out of the tax refund.

The Associated Press reports two basic statistics that highlight the problem: the average tax credit for subsidized coverage on the new health insurance exchanges is $264 a month, or $3,168 for a full 12 months, while the average the average tax refund is about $2,690.

“More than a third of tax credit recipients will owe some money back, and (that) can lead to some pretty hefty repayment liabilities,” George Brandes, vice president for health care programs at Jackson Hewitt Tax Service, told the AP.

Of course, the reverse of this situation is true as well. If an individual’s 2014 income was less than expected, they could qualify for a larger tax credit, and thus receive a larger refund from the IRS.