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March 2, 2023

IRS changes lookback period to allow taxpayers affected by certain COVID-19 postponements to claim refunds and credits

  • The IRS changed the lookback period so taxpayers that took advantage of certain postponed tax filing deadlines can still get refunds and credits that would have been precluded.
  • Many taxpayers were unaware that the postponed tax filing deadlines did not change the lookback period.

In Notice 2023-21, the IRS changed the lookback period for calculating refunds and credits for taxpayers who delayed filing their tax returns under COVID-19-related relief. For purposes of the lookback period, the Notice disregards April 15, 2020, to July 15, 2020, and April 15, 2021, to May 17, 2021, to align the lookback periods with the postponed return filing due dates.


Under IRC Section 6511(a), a taxpayer must file a claim for a refund or credit within three years of filing a tax return or two years of paying the tax, whichever period expires later. Under IRC Section 6511(b)(2), the refund or credit is limited to the tax paid within the lookback period, which is three years plus any extension for filing the return. For calendar-year taxpayers, withheld and estimated income taxes are generally deemed paid on April 15 of each year.

Notice 2020-23 postponed until July 15, 2020, the deadline for most taxpayers with a filing or payment deadline falling on or after April 1, 2020, and before July 15, 2020 (see Tax Alert 2020-0961). Notice 2021-21 postponed until May 17, 2021, the deadline for filing and payments for Form 1040 series income tax returns that were due April 15, 2021 (see Tax Alert 2021-0671).

New lookback period applies

Notice 2023-21 specifies that the filing dates were postponed, not extended. Therefore, the lookback period was not extended by Notice 2020-23 or 2021-21 and remained at three years unless a taxpayer actually secured an extension to file. Taxpayers who did not receive an extension, and did not pay their taxes before April 15, 2020, or April 15, 2021, as applicable, would only have three years from those dates to claim their refunds, not from the date they filed the return.

Under Notice 2023-21, the IRS is disregarding the periods from April 15, 2020, to July 15, 2020, and April 15, 2021, to May 17, 2021, in determining the beginning of the lookback period for claiming refunds or credits under IRC Section 6511(b)(2)(A). This will allow affected taxpayers to claim the refunds or credits by three years after the later dates. The IRS gave an example in the notice to illustrate how the calculation works with the new lookback period.


Many taxpayers were not aware of the potential disconnect created by the postponement of payment deadlines for tax years 2019 and 2020. The IRS's decision to disregard the postponement periods will avert confusion and also benefit affected taxpayers who still have refund claims.


Contact Information
For additional information concerning this Alert, please contact:
Tax Policy and Controversy
   • Kirsten Wielobob (

Published by NTD’s Tax Technical Knowledge Services group; Andrea Ben-Yosef, legal editor