I sold some stock in Dec 2019 that was gifted to me for long term capital gains. The cost basis for this stock reported in box 1e on my 1099-B was incorrect. This incorrect cost basis was also reported to the IRS.
The cost basis reported was too high, and matched exactly box 1d (proceeds). The actual cost basis (which should be the gifter's) was lower. I corrected the cost basis on Form 8949, using "code B" in column F.
I will be filing by mail/paper filing.
I have a copy of the gifter's 1099-B and "Details of 2018 Investment Activity", which shows the original purchase of this stock and the correct cost basis, before it was gifted.
My question is - am I required to send the gifter's "Details of 2018 investment activity" (or something else) in with my tax return, to support the code B/cost basis correction? Or does the IRS not want this included?
Thank you.
