A claim for refund/credit must be filed within three years from the time the tax return was filed or two years from the time the tax was paid, whichever of such periods expires later. If the claim is filed within three years of the time the return is filed, the amount of the refund/credit is limited to the tax paid within the three-year period (plus any period of extension of time to file the return) preceding the filing of the claim. This is often referred to as the “three-year look-back period.”

The non-filer should receive a certified notice of claim disallowance when a delinquent return is received by the IRS requesting a refund or credit, which is barred by the statute of limitations.