The Optimal Maturity of Government Debt. Robin Greenwood, Samuel Hanson, Lawrence Summers, 2016, Book Chapter. “The central task of debt management is to decide which debt instruments the government should issue in order to finance itself over time. What programs the government should pursue and whether the government should finance its current expenditures by collecting taxes or by borrowing are outside the purview of debt management. ¬†Historically, U.S. debt managers had three main instruments available to them: Trea sury bills with a maturity of less than one year, intermediate-maturity notes with maturities up to ten years, and long-term bonds. Inflation-protected securities were introduced in 1997 and floating-rate notes were added in 2014.Link