Did you enter a summary of your investment sales instead of entering each sale individually? If so, you have to mail (not upload) to the IRS a copy of the 1099-B detail pages from your consolidated statement. If you file your tax return by mail, attach the copy of the copy to the return, behind all the IRS forms and schedules. If you e-file, TurboTax will print a Form 8453 to attach the copy to.
