For those who complain about having to send the form to the IRS: this year (2018 tax return) Turbo Tax CLEARLY tells you (during the preparation of the data) that if you summarize you will then need to send the Form 8453 by mail. I decided to do it anyways, since I have 2 SMA's with 100-200 individual stocks each. However, while TT tells you to send the Form 8453 with the 1099-B during the preparation of the data, the printed filing instructions are not clear about the actual documents that need to be send with Form 8453. It actually says in the filing instructions: "Attach the following items to Form 8453: Form 8949 or an acceptable Continuation Sheet for Schedule D." Which, as we know from the Recommended Answer above, it's wrong. You need to send the 1099-B, not the Form 8949
