Need to file amended return for 2020

[Taxsmith]

I am a US citizen living abroad (so tax deadline is June 15). I filed on June 10th and received an email that the return has been accepted. Today I realized that I forgot to prepare form 8949 for our crypto transactions. Should I file the amended return right away or wait until I have received my refund? The crypto transactions will reduce the size of my refund, but it will still be a refund situation.

[rjs]

Do not file the amended return until the IRS has processed your original tax return and you have received the refund. You will have to pay back part of the refund from the original tax return. The amended return will show a payment owed for the amount you have to pay back.

[Taxsmith]

@rjs , thank you. Will I owe interest or penalties on the amount I have to pay back?

[rjs]

Yes, I think you will have to pay interest and penalties, but there's nothing you can do about that. After you file the amended return, just wait for the IRS to bill you for the interest and penalties. If the amount of interest and penalties is small, they might not bother.