In the ordinary course of commencing employment a new employee will execute a W-4, Withholding Exemption Certificate, to inform his or her employer of the correct filing status and number of exemptions and personal allowances to use when calculating income tax withholding. This process occurs upon hire, and sometimes changes during the year. But what happens when employees make "unusual" requests of their employer relating to withholding? This Insight provides a brief guide for employers to help determine their payroll tax obligations.