The IRS said it’s distributing about $2.4 billion to taxpayers who failed to claim a Recovery Rebate Credit on their 2021 tax returns. People who missed one of the COVID stimulus payments or had received less than the full amount were able to claim the credit. But the IRS on Friday said it discovered many eligible taxpayers hadn’t done so.

“Looking at our internal data, we realized that one million taxpayers overlooked claiming this complex credit when they were actually eligible,” IRS Commissioner Danny Werfel said in a statement.

Here’s more about the unexpected cash this group of taxpayers will soon receive:

What’s the likelihood I’ll receive a check?

Sorry, it’s probably pretty low. The IRS said most taxpayers eligible for the federal stimulus payments, formally known as Economic Impact Payments, have already received them.

The special payments announced by the IRS are being sent to those taxpayers who filed a 2021 tax return but left the data field for the Recovery Rebate Credit blank or they filled it out as $0 when they were actually eligible for the credit.

How will this work?

Eligible taxpayers don’t have to take any action. The payments will go out automatically this month and should arrive by direct deposit or check by late January 2025. They’ll be sent to the bank account listed on the taxpayer’s 2023 return or to the address IRS has on file.

Payments will vary but the maximum amount will be $1,400 per individual. The IRS has posted information online about eligibility and how the payment was calculated.

IRS plans to send separate letters to eligible taxpayers notifying them of the special payment.

What if I haven’t filed my 2021 tax return yet?

You still might be able to receive the money. However, taxpayers need to file a tax return and claim the Recovery Rebate Credit by the April 15, 2025 deadline, even if any income from a job, business or other source was minimal or nonexistent, according to IRS.

How many rounds of COVID stimulus payments were there?

There were three rounds of payments to households impacted by the pandemic, totaling $814 billion. IRS based the amounts that taxpayers received on their income, tax filing status and number of children or qualifying dependents.

In March 2020, eligible individuals received up to $1,200 per income tax filer and $500 per child under the CARES Act. In December 2020, eligible individuals received up to $600 per income tax filer and $600 per child under the Consolidated Appropriations Act. In March 2021, eligible individuals received up to $1,400 per income tax filer and $1,400 per child under the American Rescue Plan Act.