Nearly 160 million Americans were eligible for the second stimulus check, according to the US Treasury, yet millions are still waiting for their money to arrive. However, some who did receive a payment may not have actually met the requirements and could soon find themselves in the uncomfortable position of needing to return it.

With the first round of relief payments last year, the IRS said it mistakenly sent stimulus checks to ineligible people, and it's possible the same thing happened again. If you received a payment that you don't think you should have gotten -- perhaps you make more than the specified income limit, for instance -- the IRS expects you to send back the money. And depending on how you received the stimulus payment -- by paper check, EIP card or direct deposit -- there are specific ways to go about returning it.

Here are the reasons the IRS would want you to return a stimulus check paid out in error, and here's how to do it. It's also important to know your stimulus check rights and these key details about stimulus checks and taxes. (And here's what's happening with a potential third stimulus check, how much money the new payment could bring and when it might be approved.) This story is frequently updated.

Reasons you might need to return a stimulus payment

"Qualifications" refers to how the government determines who is eligible for a second stimulus check. If you fall into any of these categories and received a stimulus check, it's likely by error:

• You received a check for someone who has died -- but there's some nuance here (more below).
• You don't have a Social Security number.
• You're considered a "nonresident alien" without a US citizen spouse.
• You're a noncitizen who files federal taxes.
• Your adjusted gross income exceeds the limit; for example, $87,000 for a single taxpayer.
• You're claimed as a dependent on someone else's taxes.

Here's more information about who doesn't qualify for the $600 stimulus check.

How to send back a paper check that you haven't cashed or deposited

If any of the above situations pertain to you, you may need to send your stimulus check back. Here's how to do it for each scenario, per the IRS.

1. Write "VOID" in the endorsement section on the back of the check.

2. Do not bend, paper clip or staple the check.

3. On a separate piece of paper, let the IRS know why you're sending the check back.

4. Mail the check to the appropriate IRS location -- it varies depending on which state you live in.

How to send back a stimulus payment that you did cash or deposit

1. Use a personal check or money order and make the check payable to the US Treasury. You'll also need to write 2020 EIP and include the taxpayer identification number or Social Security number of the person whose name is on the check. 

2. On a separate piece of paper, let the IRS know why you're sending the check back.

3. Mail the check to the appropriate IRS location -- it depends on which state you live in.

Did you receive a stimulus check for someone who died?

If you received a payment for someone who died in 2019 or earlier, the IRS says you should return the entire payment "unless it was made to joint filers and one spouse is still living." If you're the living spouse, you should return half the payment -- just not more than $1,200 in all. 

However, if the check is issued in both your name and your deceased spouse's name (and therefore you can't deposit the money), you'll need to return the whole amount to the IRS. After the agency processes the returned payment, it will issue a new check with the correct amount for you.

What you can do if you still haven't gotten your stimulus check

If you're among the more than 100 million people who were eligible to receive the second $600 stimulus check and you haven't received it, you may be able to claim it as a Recovery Credit Rebate on your taxes, even if you don't usually file taxes. Alternatively, you may have to start an IRS payment trace.

If you aren't signed up for direct deposit through the IRS, now's a good time, as a third stimulus check is on the table. To do so, you'll need to add your banking information when you file your 2020 taxes this year. We also encourage you to file your taxes as early as possible this year, specifically because of stimulus checks.

To stay updated on the latest stimulus check news, check what happens now that the IRS has stopped sending second stimulus checks. If you're having stimulus check problems, do this instead of calling the IRS. Also, here's what's happening right now with a potential third stimulus payment.