The Tax Cuts and Jobs Act repealed the special rule that allowed a traditional IRA to Roth IRA conversion to be later unwound, effective for taxable years beginning after December 31, 2017. Thus, for example, under the provision, a conversion contribution to a Roth IRA during a taxable year can no longer be recharacterized as a contribution to a traditional IRA (thereby unwinding the conversion). (IRC Sec. 408A(d)(6)(B)(iii) as amended by TCJA Sec. 13611(a).

However, recharacterization is still permitted with respect to contributions. For example, an individual may make a contribution for a year to a Roth IRA and, before the due date for the individual's income tax return for that year, recharacterize it as a contribution to a traditional IRA (Conference Report). Thus, if an individual makes a Roth IRA contribution, the contribution can be converted to a traditional IRA contribution, or vice versa, provided the conversion is accomplished before the unextended due date for the return (IRA contribution must be made by the April return due date).

Note: This rule applies for conversions from a traditional IRA, SEP or SIMPLE to a Roth IRA. The TCJA-created law also prohibits recharacterizing amounts rolled over to a Roth IRA from other retirement plans, such as 401(k) or 403(b) plans (IRS FAQ).