The bond market is a financial market in which participants can issue new debt, known as the primary market, or buy and sell debt securities, known as the secondary market. This is usually in the form of bonds, but it may include notes, bills, and so on for public and private expenditures. The bond market has largely been dominated by the United States, which accounts for about 39% of the market. As of 2021, the size of the bond market is estimated to be at $119 trillion worldwide and $46 trillion for the US market, according to the Securities Industry and Financial Markets Association (SIFMA).

Debt is an obligation that requires one party, the debtor, to pay money borrowed or otherwise withheld from another party, the creditor. Debt may be owed by sovereign state or country, local government, company, or an individual. Commercial debt is generally subject to contractual terms regarding the amount and timing of repayments of principal and interest. Loans, bonds, notes, and mortgages are all types of debt. In financial accounting, debt is a type of financial transaction, as distinct from equity.