Turbotax tells me I need to submit a form 8453 because I ALSO need to submit a form 8949 because my broker did not report one stock sale to the IRS. What to mail to IRS?

[fanfare]

One stock sale?

enter the sell transaction details yourself before submitting. You will not have to mail anything.

If the transaction was not reported, tell Turbotax - "I don't have a 1099-B".

@mafiedler 

[mafiedler]

Let me clarify my original question.  I have one short term stock sale through JP Morgan where the cost basis was NOT reported to the IRS.  However, on my Form 8949 - Box B, it already shows the correct proceeds and cost basis.  On the bottom of the Capital Assets Worksheet it says "Taxpayer must mail in a statement with more details". 

TurboTax automatically printed a form 8453 with the applicable box checked for Form 8949.  Am I to submit the Form 8453 together with a copy of my Consolidated 2023 Forms 1099 and Details report that I received from JP Morgan? Does the IRS want this entire report (with many other trades where basis WAS reported), or just the single page that shows the one trade where basis was not reported?  

Thank you for your help!

[Mike9241]

an 8453 is only required when you do not detail each individual trade on form 8949 - ie your entering multiple trades on a single line in the form.

if multiple trades are properly entered on schedule D lines 1a and/or 8a and no combined trades on any other line than 8453 is not used. 

[fanfare]

There is no reason to mail anything to the IRS since your transaction detail will be sent via e-File.

Is there some other summarization on your Schedule D?

That would be indicated by Code "M" on one or more forms 8949.

@mafiedler 

[mafiedler]

This trade is the only one indicated by a Code M. It was a routine stock sale, just like the other +/- 20 trades with JPMorgan. 

[fanfare]

I can't recall seeing a post citing this behavior. It looks like a new bug in TurboTax.

OR an old bug that has caused posts with other descriptions.

@mafiedler 

cc; @Mike9241