According to USAFacts, in 2015, the federal government paid more than $220 billion in interest, which is six percent of the federal budget and more than one percent of GDP. Thus, federal interest payments are a major component of the federal budget and significantly impact on the U.S. economy. The maturity structure of federal debt--the sizes of, due dates of, and interest rates on federal debt--affects federal interest payments. Longer-term debt issued at higher interest rates increases interest payments but “locks in” those payments for a long time. Shorter-term, lower-interest debt lowers interest payments but increases the impact of changes on interest rates on the federal budget as federal debt is refinanced.
Previously, we analyzed the maturity structure of federal debt back to 1953. Below, we describe how PWBM incorporates the maturity structure of federal debt into our dynamic overlapping-generations (OLG) model to make projections of interest paid on the federal debt.