The Roth Conversion Deadline Is Dec. 31, but the Tax Bill Comes Due Jan. 15. Retirees Who Don't Prepay Get Hit With a Penalty on Top. - 24/7 Wall St.

What the report says

Completing a Roth conversion on December 31 locks in the tax year, but the IRS starts running a penalty clock long before April, and most retirees discover this only after the damage is already done.