Nolo's Plain-English Law Dictionary

Social Security Tax

A portion of the FICA (Federal Insurance Contributions Act) tax that is 12.4% of an individual's net earned income. The employee's share of the Medicare tax is 6.2% of wages up to a certain limit (called the Social Security Wage Base) that increases each year. The employer's share of the Medicare tax is 6.2% of an employee's wages up to that limit.
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