As of September 30, 2020, 64 percent of the outstanding amount of marketable Treasury securities held by the public (about $13.1 trillion) was scheduled to mature in the next 4 years. Current coupon rate is around 2,5 percent

During the past decade, the federal government’s debt increased at a faster rate than at any time since the end of World War II, outstripping economic growth over that period. At the end of 2019, federal debt was higher than at any other time since just after the war.

When the federal government runs an annual budget deficit, the Department of the Treasury borrows money to make up the difference between spending and revenue. Then, if special funds like the Medicare trust fund have surpluses, the “extra” revenue is lent to the rest of the federal government.

The federal debt is the total amount of money that the federal government owes, either to its investors or to itself. Total federal debt rose to $26.9 trillion at the end of fiscal year 2020, equal to about 79 percent of GDP, a higher percentage than at any other time since just after World War II.

To finance the government’s activities, the Treasury issues securities—collectively labeled debt held by the public—that differ in time to maturity, the ways they are sold to investors, and the structure of their interest payments. Marketable securities make up the lion’s share of that debt, and nontradable securities, such as savings bonds, make up the rest.

The Treasury sells securities in the capital markets—often through a primary dealer intermediary­—to various U.S. buyers (such as the Federal Reserve System, mutual funds, financial institutions, and individual people), to private investors overseas, and to the central banks of other countries. Domestic investors currently own about three-fifths of outstanding debt held by the public.