The employer as a tax withholding agent must perform the year-end settlement of exact payroll withholding taxes for and on behalf of its employees in February of following year after each year end mandatorily as required by the IITL of Korea.
In this connection, the employer should reflect the results of year-end settlement in the February payroll of the following year accordingly. Any overpayment resulting from year-end settlement is used to offset the payroll taxes due in February of the following year and onward until fully utilized. For any underpayment resulting from the year-end settlement, the employer should withhold additionally from the February payroll and remit to the tax office as scheduled by March 10 of the following year (by March 12, 2018 for year 2017).
For the year-end settlement processing, the employees should gather and submit supporting documents to claim tax deductions/credits.