What determines if an employee is exempt from FICA coverage if they are part of a retirement plan?

The exemption of an employee from Federal Insurance Contributions Act (FICA) coverage due to their participation in a retirement plan is primarily determined by the date of hire. Specifically, whether an employee is covered by FICA can depend on the rules applicable to those who were hired before or after certain cutoff dates established by the plan.

For example, employees who were hired before a specific date may be exempt from FICA taxes if their employer offers a qualified retirement plan that meets certain criteria, while those hired after that date may not have the same exemption available. This is often tied to the particulars of the plan and the employee's relationship to the employer at the time of hire, making the date of hire a key determinant.

Understandably, other factors like the nature of the retirement plan, the type of government employment, or the enrollment date could play a role in other contexts but are not the primary basis for FICA exemption in relation to retirement plans.