I failed to include SS income when filing in 2020, so I am amending 2020 to include it. The 2020 SSA-1099 shows that SS income for 2019 was paid in 2020. The amount in Box 5 of the SSA-1099 includes the 2019 income. I showed the 2019 income amount as a lump sum payment. In that input dialogue box it lists it as 2019 as the year for which payment was received. After I entered the lump sum amount the federal tax due decreased. On the summary page it shows the full amount from Box 5a, which includes the lump sum payment.
My question is whether I need to amend my 2019 taxes to include the lump sum payment amount?
Thank you in advance for any advice,
Siamesefan
