Time is running out for families with kids to make any changes to information the IRS has on file for their last child tax credit payment of the year.

Families have until Monday, Nov. 29, to reach out to the agency and have it reflected in the final monthly payment, set to go out on Dec. 15.

There are a few reasons why families may want to send the IRS any new information, which they can do through the agency's child tax credit portal.

They can change the address where checks are mailed or shift the bank account to which their payment is deposited. They can also opt out of receiving the final monthly installment.

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In addition, families who have had a significant change in income from 2020 may want to send the IRS up-to-date figures. If they made less money in 2021 than the previous year, they may be eligible for a larger credit.

On the flip side, if they made more money in 2021 than 2020, they may have gotten more than they're owed through the credit. In extreme cases, such as a family becoming ineligible for the credit due to a jump in income, they may have to pay back the advance monthly payments they got come tax time.

To be sure, most families do not need to make any changes to the information provided to the agency and are set to receive the final payment come December. They will get the second half of the credit in a lump sum when they file their 2021 taxes next year.

It's also too late for families with eligible children who haven't been receiving payments — generally because they do not file taxes — to sign up for the credit. However, they can still receive the full benefit in a lump sum next year by filing a tax return.

The American Rescue Plan in March expanded the existing child tax credit, adding advance monthly payments and increasing the benefit to $3,000 from $2,000, with a $600 bonus for kids under the age of 6, for the 2021 tax year. The first half of that credit has been delivered in monthly payments of up to $300 for children under 6 and $250 for those aged 6 to 17.

Going forward, it's still unclear if the expanded child tax credit will continue. On Friday, the House passed a $1.7 trillion version of the Democrat budget plan, sending to the Senate.

There, it must have all 50 Democratic Senators' votes to pass.  

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