the level of the national debt is limited by
National debt of the United States Historically, the US public debt as a share of gross domestic product (GDP) has increased during wars and recessions, and subsequently declined. The ratio of debt to GDP may decrease as a result of a government surplus or due to growth of GDP and inflation. For example, debt held by the public as a share of GDP peaked just after World War II (113% of GDP in 1945), but then fell over the following 35 years. In recent decades, aging demographics and rising healthcare costs have led to concern about the long-term sustainability of the federal government's fiscal policies.[3] The aggregate, gross amount that Treasury can borrow is limited by the United States debt ceiling.[4]
National debt of the United States As of April 30, 2018, debt held by the public was $15.3 trillion and intragovernmental holdings were $5.7 trillion, for a total or "National Debt" of $21 trillion.[5] Debt held by the public was approximately 77% of GDP in 2017, ranked 43rd highest out of 207 countries.[6] The Congressional Budget Office forecast in April 2018 that the ratio will rise to nearly 100% by 2028, perhaps higher if current policies are extended beyond their scheduled expiration date.[7] As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest being China (about $1.18 trillion) then Japan (about $1.06 trillion).[8]