The IRS sometimes questions rollovers that span the year-end boundary because they will not receive the Form 5498 showing the rollover until more than a year after the rollover occurred, in this case a 2018 Form 5498 that you and they will receive from the financial institution in mid-2019. In case the IRS does question the rollover properly shown on your 2017 tax return, simply be prepared with account statements to show that the rollover was completed within the 60-day rollover window.
