for 2020 TurboTax revised the security sales worksheet (1099-B). all trades coded type A with no wash sales can be entered as just totals in the summary section of the worksheet. they do not get reported on form 8949. is it possible you entered the detail in the detail section and then reported them again in the summary section (top right)
the easiest way I can think of to check for duplication is to add up the proceeds on lines 1-3 and 8-10 of schedule D and compare it to the total proceeds reported on the 1099-B
Thank you for your response. I uploaded my transaction data from Morgan Stanley, so the detail was input to TurboTax by that upload. The 8949 was thus generated by TurboTax, as was the data populated into Schedule D. I cannot determine if this is an issue or not. The TurboTax text states to leave line 1a on Schedule D blank if also reporting on 8949. I don't appear to have control over this. Is this possibly a bug?
This is not an issue with your return or shouldn't be anyway.
**Mark the post that answers your question by clicking on "Mark as Best Answer"