If timely returned before the due date (or extended due date if a timely extension is filed) and any earnings are also returned then of this was a 2019 excess removed in 2020 the distribution will be reported on a 2020 1099-R next January. The returned contribution will not be taxable but any earnings will be taxable in the tax year that the contribution was for, not the year returned.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
