One result of persistent fiscal imbalance is growing debt and net interest costs.Net interest is currently the fastest-growing "program" in the budget and if unchecked, threatens to crowd out spending for other national priorities. This report was done under the Comptroller General's authority and examines the Department of the Treasury's (Treasury) growing use of unscheduled cash management bills (CM bills). GAO describes (1) when Treasury uses CM bills and why, (2) the advantages and disadvantages of CM bills, and (3) steps taken by Treasury to reduce the overall borrowing costs associated with CM bills. GAO identifies possible options Treasury could consider to reduce the use and cost of CM bills further.