In fiscal year 2020, which ended on September 30, the federal budget deficit totaled $3.1 trillion—more than triple the shortfall recorded in fiscal year 2019. Much of that amount was the result of the economic effects of the novel coronavirus pandemic and the legislation enacted in response; CBO and the staff of the Joint Committee on Taxation estimated that the legislation would add $2.3 trillion to the deficit. During the first six months of 2020, the deficit totaled $0.7 trillion; it rose by $2.4 trillion in the second half of the fiscal year. The deficit in 2020 was equal to 14.9 percent of the nation’s gross domestic product (GDP), up from 4.6 percent in 2019 and 3.8 percent in 2018; the deficit was the largest as a percentage of GDP since 1945. As a result of the deficit and federal borrowing for other reasons—primarily to increase the Treasury’s cash balance—federal debt held by the public rose to 100.1 percent of GDP, up from 79.2 percent of GDP at the end of fiscal year 2019.