TurboTax Desktop no longer allows you to attach Form 1099-B electronically. They say the online version does allow it. I cannot fathom why it would be different but that's what TT says. To further complicate it, TT Business (desktop) did not offer any further mailing instructions for the Form 1099-B, although on the 8949 they clearly typed out "[broker name] See Attached Stmt". The Form 8453-FE (for estates and trusts) doesn't include the checkboxes that Form 8453 for individuals does. So I guess I'm just mailing a copy of the signed Form 8453-FE (which is the Declaration of Fiduciary to approve the e-filing) with the broker statement attached.
The instructions for 2024 Form 8949 state (on page 4 of the PDF): "E-file. If you e-file your return but choose not to report each transaction on a separate row on the electronic return, you must attach Form 8949 to Form 8453 (or the appropriate form in the Form 8453 series) and mail the forms to the IRS. (However, you can't attach a paper Form 8949 to Form 8453-FE.)..."
TurboTax could have eliminated hours of frustration if they just allowed their desktop version users to attach the broker statement to the e-file. If it's okay to do that in their online version, why not in their desktop version?
