Pre-Tax Deductions are the money withheld from an employee’s wages for benefits that reduce taxable wages, such as Section 401(k) or Section 403(b) contributions, Section 125 group health insurance premium contributions. Post-Tax Deductions are the money withheld from an employee’s wages that do not reduce taxable wages, such as Section 401(k) or Section 403(b) loan repayments, child support payments, alimony payments, other wage garnishments, membership dues, etc.