A new client, who is self employed, did not claim IRS sick leave tax credits on his 2020 tax return and I'm trying to determine if the election to use the prior year (2019 in this case) self-employed earnings can be made on an amended 2020 return subsequent to October 15, 2021. I cannot find anything.
I did not see an original due-date requirement for using a prior year substitution in IRC 163(j)(10)(B)(i) related to interest expense.
Has anyone see something authoritative regarding this?