Should I attach a copy of my 1099-B if it was sent to the IRS by my brokerage firm?

[ameliaguy]

Do I have to upload my 1099-B if my broker already submitted it?

[xmasbaby0]

Yes you have to enter it on your tax return.   Financial institutions send copies of any sort of 1099 they issued to the IRS.  The information you enter on your tax return has to match what they sent, just like your W-2 has to match what your employer sent in with your Social Security number on it.

[fanfare]

@ameliaguy 

If you are not excused by the detail reporting exception,
IRS requires details of your SELL transactions to be supplied on some Form 8949,
or on your other forms (e.g. consolidated 1099-B or spreadsheet) which have the same information and in the same manner as Form 8949.

This is so, even when the broker has sent details to the IRS already.

The exception does not include wash sales, since they have an adjustment.

Detail Reporting Exception: if you summarize Category A or Category D, Form 8949 is not needed for transactions without adjustments. No mailing is necessary. No attachment is necessary.