@fanfare wrote:
Clarification--
- IF you pay a sufficiently large Estimated Tax payment for fourth quarter (due by 1/15/21), AND
- you check box C on Form 2210,
I don't believe reason "C" applies in this case. The instructions say "If your income varied during the year because, for example, you operated your business on a seasonal basis or had a large capital gain late in the year, you may be able to lower or eliminate the amount of one or more required installments by using the annualized income installment method."
That is not the case here. The taxpayer is under-withheld because their W-4 form(s) wasn't right. They did not have a variable source of income. I would rather suggest that the taxpayer make a large enough estimated payment to get fully paid up, and then request an administrative waiver if a penalty is assessed. Including a form 2210 when no tax is owed may clue the IRS in to look further.
