Budget Issues: Treasury's Interest Rate Calculation Changes

Pursuant to a congressional request, GAO reported on the Department of the Treasury's decision to change the calculation of the interest rates used since 1980 to determine the investment returns for a number of government trust funds, including Social Security and Medicare, focusing on: (1) how and why Treasury changed its rules for calculating interest rates in 1980 and 1998; (2) the effects of these changes on the unified budget and on the financial status of Social Security and Medicare trust funds; and (3) what other trust funds were affected by Treasury's decision.