According to the 2016 Summary of Annual Reports by the trustees, the major source of funding for the Social Security and Medicare programs is the payroll tax you and your employer pay, or that you pay as a self-employed worker. In addition, about 13% of the funding comes from the taxation of social security benefits – those taxes you pay with your federal income tax return when you collect social security benefits and your income is above a certain amount. Other sources of funding come from the interest earned from the Treasury on the program assets, monthly premiums paid for Medicare benefits, and general tax revenue.
McFadyen & Sumner, CPAs PA 