Which of the following is NOT included in FICA's definition of wages?

The correct choice is that the first six months of sick pay is not included in FICA's definition of wages. The Federal Insurance Contributions Act (FICA) specifically outlines what constitutes "wages" for tax purposes, and certain types of compensation can be exempt from FICA taxation.

Sick pay is generally not subject to FICA taxes for the initial six months, as it is considered to be a form of income replacement rather than earnings for services rendered. This reflects the principle that FICA taxes are designed to apply to actual wages for work performed rather than to payments that are compensatory but not for work done.

In contrast, severance pay, commissions, and year-end bonuses are typically included in FICA's definition of wages because they are all considered compensation for employment services. These forms of pay are associated with the employee’s work and therefore fall under the scope of FICA taxation. Thus, they contribute to Social Security and Medicare funding, which supports social insurance programs.