I need to use 2020 AGI for the third economic impact payment since my RMD was waived for that year. 2019 and 2021 AGI will be over the threshold. I have two limited partnerships for which I will not receive a 2020 K-1 until early September 2021, past the Additional Payment Determination Date (APDD), but I have estimates for those K-1s. Should I file before the APDD (8/15/21) and then file a 1040X after the APDD when the official K-1s are received? If the 1040X puts my 2020 income over the threshold, will any of the stimulus payment be clawed back? I assume it would be; otherwise, anyone could file now and then amend post-APDD. Thanks.
You would have to pay back any excess stimulus payments you received when you file your amended return if you were not entitled to some or all of it. It may be best to file an extension, then wait until you have all of your K-1's before you file your tax return.
In your situation filing now and amending later is a valid option so you can catch the "plus up" deadline.
I have filed an extension, and the return is extended to 10/15/21. But as I stated, I will not receive the K-1s until early September, past the Additional Payment Determination Date. If I file my return after that date (as would be the case if I wait for the K-1s), the Economic Impact Payment (EIP) would then be based on 2021 AGI, not 2020 AGI. My 2021 AGI will be above the threshold for an EIP. That is my dilemma,