What are the major federal payroll taxes, and how much money do they raise? Q.What are the major federal payroll taxes, and how much money do they raise? A.Payroll taxes are levied to finance Social Security, the hospital insurance portion (Part A) of Medicare, and the federal unemployment insurance program. Revenue totaled just over $1 trillion, or about 6 percent of GDP, in fiscal year (FY) 2015 (figure 1). Read more about What are the major federal payroll taxes, and how much money do they raise?