HR Training 2020 - Withholding Computations for Unusual Circumstances to Avoid Under-withheld Tax Penalties

Overview
Employer federal income tax withholding is intended to collect, throughout the year, the approximate the amount of the employee’s tax for the year. The wage bracket and percentage methods are the primary methods for computing the amount to withhold, but sometimes they just don’t seem to get the right result.
When supplemental wages are added to the equation, the prescribed aggregate method and optional flat rate method frequently result in too much or too little withholding.
Payroll professionals sometimes experience a flood of revised W-4 Forms just before and after scheduled bonus payments. This creates additional work and opportunities for mistakes for the payroll department and may not affect the withholding in the way the employee expected.