Use of payroll periods.
(ii) Use of payroll periods. For payroll periods that are one week, two weeks, or semi-monthly in duration, an employer is permitted to treat as a measurement period a period that ends on the last day of the payroll period preceding the payroll period that includes the date that would otherwise be the last day of the measurement period, provided that the measurement period begins on the first day of the payroll period that includes the date that would otherwise be the first day of the measurement period. An employer may also treat as a measurement period a period that begins on the first day of the payroll period that follows the payroll period that includes the date that would otherwise be the first day of the measurement period, provided that the measurement period ends on the last day of the payroll period that includes the date that would otherwise be the last day of the measurement period. For example, an employer using the calendar year as a measurement period could exclude the entire payroll period that included January 1 (the beginning of the year) if it included the entire payroll period that included December 31 (the end of that same year), or, alternatively, could exclude the entire payroll period that included December 31 of a calendar year if it included the entire payroll period that included January 1 of that calendar year.