Federal payroll tax that funds Social Security and Medicare. Employees pay 7.65% of wages; employers match it.
The Federal Insurance Contributions Act (FICA) is a U.S. payroll tax split between Social Security (6.2% on wages up to the annual cap) and Medicare (1.45% on all wages, plus a 0.9% Additional Medicare Tax on high earners). Employers match the employee share dollar-for-dollar; self-employed workers pay both halves via SECA.