This sort of question should be resolved by looking at the IRSu2023 official instructions for the tax form and year in question. You only need to attach such items as the IRSu2023 official instructions direct you to attach. Recently there has been a trend of requiring fewer attachments.For the sake of answering this specific question for this specific year, there appears to be no such requirement. The Form 1099-B was already reported to the IRS and the Schedule D instructions make no mention of attaching it. You may need to attach a u201cstatement required under Regulations section 1.1(h)-1(e).u201d Id. lines 10 and 18.For actual advice on filling in your forms, consult a tax attorney or accountant.