The IRS issued notice 2018-14 to provide guidance on the withholding rules that were changed by the tax cuts and job act.

This notice…

1.  Extended the effective period of forms W-4, employee’s withholding allowance certificates until February 28, 2018, and permits the use of the existing 2017 form W-4 to claim exemption from withholding for 2018 until 30 days after the IRS issues a new 2018 Form W-4;
2. Temporarily suspends the rule requiring that employees notify their employer regarding changes in status that effect their withholding within 10 days;
3. Provides the new rate of optional withholding on supplemental wages; and
4. Provides that withholding on periodic payments when no withholding certificate is in effect be based on treating the payee as married and claiming three withholding allowances.