(a) No withholding allowance certificate on file. A withholding allowance certificate furnished to the employer in any case in which no previous withholding allowance certificate is in effect with such employer, takes effect as of the beginning of the first payroll period ending, or the first payment of wages made without regard to a payroll period, on or after the date on which such certificate is so furnished.

(b) Withholding allowance certificate on file. Except as provided in paragraph (c) of this section, a withholding allowance certificate furnished to the employer in any case in which a previous withholding allowance certificate is in effect with such employer takes effect as of the beginning of the first payroll period ending (or the first payment of wages made without regard to a payroll period) on or after the 30th day after the day on which such certificate is so furnished. However, the employer may elect to put a withholding allowance certificate into effect earlier, beginning with any payment of wages on or after the day on which the certificate is so furnished.

(c) Withholding allowance certificate furnished to take effect in next calendar year. A withholding allowance certificate furnished to the employer pursuant to section 3402(f)(2)(C) (see § 31.3402(f)(2)-1(e) or § 31.3402(l)-1(c)) which effects a change for the next calendar year, does not take effect, and may not be made effective, with respect to the calendar year in which the certificate is furnished.

(d) Applicability date. The provisions of this section apply on and after October 6, 2020. Taxpayers may choose to apply this section on or after January 1, 2020 and before October 6, 2020. For rules that apply before October 6, 2020, see 26 CFR part 31, revised as of April 1, 2020.