What interest rate do the Social Security Trust Funds earn?

Frequently readers comment that the government stole the Social Security trust fund money or that the tax money should have been invested.

In fact, when there was a surplus of incoming payroll taxes over outgoing benefits, that surplus was invested and here is interest paid.

The rate of interest on special issues is determined by a formula enacted in 1960. The rate is determined at the end of each month and applies to new investments in the following month.

The numeric average of the 12 monthly interest rates for 2013 was 1.875 percent.

The annual effective interest rate (the average rate of return on all investments over a one-year period) for the OASI and DI Trust Funds, combined, was 3.79 percent in 2013. This higher effective rate resulted because the funds hold special-issue bonds acquired in past years when interest rates were higher.