Claims for refund come in two part. The parts are found in Section 6511(a) and (b). First, Section 6511(a) requires claims for the refund to be filed within a period of three years from the time the tax return was filed or two years from the time the tax was paid. But there is more. Section 6511(b) then tells taxpayers that the amount of the refund is limited. It is limited to the tax paid within the three-year period immediately before the claim is filed, if the taxpayer filed the claim within three years from filing the return. Sounds a bit squirrely, right? It is important to note that if the claim is filed within subsection (a)’s two-year period, then the refund is limited to the tax paid within the two years immediately preceding the claim; but if it is filed more than three years from the time the return was filed, it does not reach any of those taxes paid. Thus, taxpayers can file a claim for refund timely (two years from the time the tax is paid), but still be barred from receiving any part of the refund paid three years from the time the tax return is filed. The statute of limitation rules, and “look-back” rules, for claims for refund can challenge even the most seasoned tax lawyers.