Debt markets are where governments, corporations, and other organizations raise money by borrowing from investors through bonds and similar instruments. Every transaction creates a contract: the borrower promises to repay the principal plus interest on a set schedule, and the investor collects income until the debt matures or is sold. The U.S. fixed-income market alone held roughly $48.9 trillion in outstanding securities as of the third quarter of 2025, making it one of the largest pools of invested capital in the world.1SIFMA. US Fixed Income Securities Statistics That borrowing funds everything from federal highway projects to corporate payroll lines of credit.
How Borrowing and Trading Actually Happen
Debt markets operate in two layers. In the primary market, a borrower creates a new bond or note and sells it to investors for the first time. Investment banks typically manage this process, buying the new debt from the issuer and reselling it to institutional buyers and the public. For most public offerings, the issuer files a registration statement with the Securities and Exchange Commission under the Securities Act of 1933, which requires detailed disclosure about the borrower’s finances and the terms of the debt.2Office of the Law Revision Counsel. 15 USC 77c – Classes of Securities Under This Subchapter
Not every offering goes through full registration. Private placements under Regulation D let issuers sell debt to accredited investors without registering with the SEC, provided they follow rules about who can buy and how the securities are marketed.3SEC. Private Placements – Rule 506(b) Securities sold this way cannot be freely resold without their own registration or another exemption.4eCFR. Regulation D – Rules Governing the Limited Offer and Sale of Securities Without Registration Under the Securities Act of 1933
Once the initial sale wraps up, the debt enters the secondary market, where investors trade it among themselves. The original borrower is no longer involved in these trades. Prices shift constantly based on prevailing interest rates, the borrower’s financial health, and broader economic conditions. A liquid secondary market matters because it lets investors exit positions quickly, which in turn makes investors more willing to buy new debt in the first place. Without easy resale, borrowers would have to offer higher interest rates to attract buyers worried about being locked in.
What Gets Bought and Sold
The debt market covers a wide range of instruments, each designed for different borrowers, timelines, and risk profiles.
Treasury Securities
The U.S. government borrows by issuing Treasury securities, which are backed by the full faith and credit of the federal government.5TreasuryDirect. Savings Bonds: About Treasury bills mature in one year or less and are sold at a discount rather than paying periodic interest. Treasury notes run from two to ten years and pay interest every six months. Treasury bonds extend past ten years, with the longest maturing in 30 years. The government also issues Treasury Inflation-Protected Securities (TIPS), whose principal adjusts with inflation, and floating rate notes, whose interest payments reset periodically. Individual investors can buy directly through TreasuryDirect for as little as $25.
Municipal Bonds
State and local governments issue municipal bonds to fund public projects like schools, roads, and water systems. The key draw: interest earned on most municipal bonds is excluded from federal income tax.6Office of the Law Revision Counsel. 26 USC 103 – Interest on State and Local Bonds That exclusion has limits. It doesn’t apply to certain private activity bonds, arbitrage bonds, or bonds that aren’t in registered form.7Office of the Law Revision Counsel. 26 USC 149 – Bonds Must Be Registered to Be Tax Exempt; Other Requirements Because of the tax advantage, municipal bonds tend to offer lower stated yields than comparable taxable bonds, but the after-tax return can be higher for investors in upper tax brackets.
Corporate Bonds
When companies need long-term financing, they often issue corporate bonds. The borrower agrees to pay a fixed or floating interest rate, called the coupon, on a schedule until the bond matures, at which point the face value is returned. Investment-grade bonds come from financially stable companies and carry lower yields. High-yield bonds, sometimes called junk bonds, come from borrowers with weaker credit profiles and compensate investors with higher interest rates to offset the greater chance of default.
For publicly offered corporate bonds, federal law requires the issuer to use a formal trust indenture overseen by an independent trustee. The Trust Indenture Act of 1939 requires the trustee to be a corporation with no material conflicts of interest with the issuer, and its job is to enforce the bond’s terms on behalf of investors.8GovInfo. Trust Indenture Act of 1939 The indenture spells out payment schedules, what counts as a default, and what remedies investors have if the borrower breaks its promises.
Commercial Paper
Companies with strong credit ratings use commercial paper to cover short-term needs like payroll or inventory purchases. Commercial paper is an unsecured promissory note that typically matures within 30 days, though terms can stretch up to 270 days.9Federal Reserve. Commercial Paper Rates and Outstanding Summary – About Commercial Paper That ceiling isn’t arbitrary. The Securities Act exempts notes with maturities of nine months or less from SEC registration, so staying under 270 days lets issuers skip the time and expense of a full registration filing.2Office of the Law Revision Counsel. 15 USC 77c – Classes of Securities Under This Subchapter The tradeoff: investors get no collateral backing the note and rely entirely on the issuer’s ability to pay.
Certificates of Deposit
A certificate of deposit is a deposit placed with a bank for a fixed term at a set interest rate. CDs are among the safest debt instruments because deposits at FDIC-insured banks are covered up to $250,000 per depositor, per institution. In exchange for that safety, early withdrawal typically triggers a penalty, and yields tend to be lower than riskier alternatives.
How Bond Prices and Yields Relate
Bond prices and interest rates move in opposite directions, and this is the single most important pricing relationship in debt markets.10Federal Reserve Bank of St. Louis. Why Do Bond Prices and Interest Rates Move in Opposite Directions Suppose you hold a bond paying 4% and newly issued bonds start paying 5%. No buyer will pay full price for your 4% bond when they can buy a new one at 5%, so your bond’s market price drops. The reverse is also true. If new bonds pay only 3%, your 4% bond becomes more attractive and its price rises above face value.
Yield to maturity (YTM) captures this dynamic by calculating the total annual return you’d earn if you bought a bond at its current market price and held it until maturity. YTM accounts for the coupon payments, the face value you’ll receive at maturity, the price you paid, and how many years remain. When a bond trades below its face value, at a discount, YTM is higher than the coupon rate. When it trades above face value, at a premium, YTM is lower. Watching YTM rather than just the coupon rate gives you a much clearer picture of what you’ll actually earn.
Credit Ratings and the Risks Investors Carry
Debt instruments are often called “fixed income” because the payment schedule is set in advance, but that predictability doesn’t make them risk-free. Credit ratings try to measure one piece of the risk picture up front.
Nationally recognized statistical rating organizations assign letter grades on a scale running from AAA at the top down through D for default.11SEC. The ABCs of Credit Ratings The critical dividing line falls between BBB- and BB+. Anything rated BBB- or above is considered investment grade, meaning the borrower carries relatively low default risk. Anything below is non-investment grade, often called speculative or high-yield. An investment-grade rating gives a borrower access to cheaper financing because investors demand less compensation for the risk. A downgrade from investment grade to high yield can spike borrowing costs overnight, since many pension funds and insurance companies are restricted to holding only investment-grade debt. The agencies issuing these ratings must register with the SEC under the framework set by the Credit Rating Agency Reform Act of 2006, which requires disclosure of their methodologies, performance track records, and potential conflicts of interest.12Office of the Law Revision Counsel. 15 USC 78o-7 – Registration of Nationally Recognized Statistical Rating Organizations
Three risks deserve the most attention from any debt investor.
Interest rate risk. When market interest rates rise, the value of existing bonds falls because newer bonds offer better returns. The longer a bond’s remaining term, the more its price swings with rate changes. An investor who needs to sell a long-term bond before maturity during a rising-rate environment can take a real loss. If you bought a bond paying 0.34% in 2020 and tried to sell it in 2023 when comparable bonds were paying 3.58%, you’d have to accept a steep discount.10Federal Reserve Bank of St. Louis. Why Do Bond Prices and Interest Rates Move in Opposite Directions Investors who hold to maturity avoid this problem entirely, since they receive the full face value at the end, but the opportunity cost of being locked into a below-market rate is still real.
Inflation risk. Fixed coupon payments lose purchasing power when inflation rises. If your bond pays 3% and inflation runs at 4%, your real return is negative. This hits long-term bondholders hardest because the erosion compounds over years. TIPS address this directly by adjusting principal to track the Consumer Price Index, but most corporate and municipal bonds offer no such protection.
Credit risk. This is the chance the borrower simply can’t pay. U.S. Treasury securities are widely considered free of credit risk because the federal government controls its own currency. Corporate bonds carry varying degrees of credit risk depending on the company’s financial health. When a borrower defaults, investors may recover only a fraction of their investment through bankruptcy proceedings or debt restructuring. The gap between a corporate bond’s yield and a Treasury bond’s yield of similar maturity, known as the credit spread, reflects how much extra compensation the market demands for taking on that default risk. Widening spreads signal growing investor concern about a borrower or the broader economy.
How Debt Income Is Taxed
How the IRS treats your debt market earnings depends on whether the income comes from interest payments or from selling the instrument at a profit. Interest income on corporate bonds, CDs, and Treasury securities is taxed as ordinary income at federal rates ranging from 10% to 37% for 2026, depending on your bracket. If you sell a bond for more than you paid and you’ve held it for more than a year, the profit qualifies as a long-term capital gain, taxed at 0%, 15%, or 20% depending on your income level. Short-term gains on bonds held a year or less are taxed at ordinary income rates.
Municipal bond interest is the notable exception. Federal law excludes interest on most state and local bonds from gross income.6Office of the Law Revision Counsel. 26 USC 103 – Interest on State and Local Bonds Many states also exempt their own bonds from state income tax, which can stack the savings further. One wrinkle worth knowing: if you sell a bond at a loss and buy a substantially identical one within 30 days before or after the sale, the wash sale rule disallows the tax deduction on that loss. The disallowed loss gets added to the cost basis of the replacement security instead.
How Debt Markets Differ From Stock Markets
The core distinction is the legal relationship. When you buy a bond, you become a creditor. The borrower owes you money on a schedule, and the terms are locked into a contract. When you buy stock, you become a partial owner. You share in profits if they come and absorb losses if they don’t, with no guaranteed return of your investment.
That difference matters most when a company fails. Federal bankruptcy law establishes a strict payment hierarchy. In a Chapter 7 liquidation, the estate’s assets go first to priority creditors, then to general unsecured creditors, then to penalty and punitive damage claimants, and only after all of those are satisfied does anything flow to equity holders.13Office of the Law Revision Counsel. 11 USC 726 – Distribution of Property of the Estate Shareholders often receive nothing. In a Chapter 11 reorganization, the company continues operating while restructuring its debts, but the same priority principles apply to any reorganization plan.14Office of the Law Revision Counsel. 11 USC Chapter 11 – Reorganization
Equity offers the potential for large gains if a company’s value grows, since there’s no ceiling on stock price appreciation. Bonds cap your upside at the agreed-upon interest rate and the return of your principal. In exchange for that ceiling, you get legal priority over shareholders, a predictable income stream, and contract terms enforceable in court. Most financial advisors treat bonds as a stabilizing counterweight to the volatility of stocks, and the balance between the two depends on your timeline, risk tolerance, and income needs.