While preparing to start my 2021 taxes I realized I forgot to include a 1099-R for a 401k "in plan" conversion of after-tax money to a 401k Roth when I did my 2020 taxes. Part of this conversion was taxable due to gains on the after tax contributions which, of course, impacts my 2020 return such that I will need to amend 2020.
Should I do the 2020 amendment and start my 2021 taxes based on that amendment? It will go in the mail only about a week or two before my 2021 taxes are due (which I will e-file) and I will owe both federal and state a few dollars extra. Will this cause confusion and problems with the IRS since my 2020 amendment will not yet be processed when they receive my 2021 return?
Or, should I base my 2021 taxes on my original 2020 filing and then later amend 2021 if necessary due to the 2020 amendment?
I suppose the third alternative is to put together two packages (amended 2020 and 2021) and snail mail them together with a note explaining that 2021 is based on the amended 2020 filing.
Any expert advice would be greatly appreciated.
Billy
