This article examines the US Treasury's decision to introduce a new financial instrument -- Treasury bills -- in 1929. The article shows that Treasury officials were willing to commit the resources required to introduce the new security in order to mitigate several flaws in the structure of Treasury financing operations. The article begins by describing in Section 2 the structure of Treasury financing operations in the mid-1920s and explaining how that structure had evolved in support of an important objective of federal fiscal policy: paying down, as expeditiously as possible, the debt incurred in the course of financing World War I. Section 3 describes the flaws in the structure of Treasury financing operations, and Section 4 shows how Treasury officials planned to correct or mitigate the flaws with Treasury bills. The evolution of bill financing in the early 1930s is described briefly in Section 5. Section 6 concludes.