The national debt refers to the direct liabilities of the federal government. It consists of the public debt, which is the debt issued by the U.S. Department of the Treasury to individuals, corporations, state, local and foreign governments; and intragovernmental holdings, which is the debt held by government accounts.
Public debt is either marketable or non-marketable. Marketable debt securities include bills, notes, bonds and treasury inflation-protected securities (TIPS). You can trade them in the secondary market through your broker or directly through the Treasury’s TreasuryDirect Program. Treasury bills, notes and bonds are debt securities with short-to-long term maturities that make periodic interest payments. TIPS are inflation-linked securities with variable maturities and periodic interest payments.
Non-marketable debt securities cannot be traded, but can be redeemed after being held for at least one year. The two primary types of non-marketable securities are savings bonds, which are low-risk savings vehicles that offer protection against inflation; and state and local government series bonds, or SLGS. These SLGS securities are offered for sale to issuers of state and local government tax-exempt debt through the Treasury’s SLGSafe Internet application. Other types of non-marketable securities include the domestic, foreign, Rural Electrification Authority and Government Account Series securities.
Intragovernmental holdings are mainly Government Account Series securities held by government trust funds, such as the Social Security Trust Funds, revolving funds and other special funds. According to the Treasury’s Monthly Statement of the Public Debt for September 2010, most of the approximately $4.5 trillion in intragovernmental holdings was in non-marketable GAS securities.
Gross Federal Debt
The gross federal debt is the sum total of the public debt and the intragovernmental holdings. According to the Treasury’s Monthly Statement of the Public Debt for September 2010, the gross federal debt was approximately $13.5 trillion, consisting of about $8.5 trillion in marketable securities and about $5 trillion in non-marketable securities.