Last Modified: July 7, 2026
Table of Contents
FINRA STUDENTS | FINANCIAL REGULATION COURSES
A bond is a debt security — a formal, legally enforceable instrument representing a loan extended by an investor to an issuer — in which the issuer promises to pay the investor a specified rate of interest, called the coupon, at defined intervals over the life of the instrument, and to return the face value of the loan, called the par value or principal, on a specified future date called the maturity date.
Making the bond the foundational fixed income instrument through which governments, corporations, municipalities, and other entities raise the capital needed to fund their operations, finance infrastructure, refinance existing obligations, and support long-term investments.
The United States bond market is the largest fixed income market in the world — encompassing United States Treasury securities representing the borrowings of the federal government, agency and mortgage-backed securities, corporate bonds issued across the full credit quality spectrum from investment grade to high yield, and municipal bonds issued by state and local governments whose interest is generally exempt from federal income tax, with total outstanding debt exceeding fifty trillion dollars as of recent estimates and daily trading volumes that dwarf those of the equity markets.
For securities industry professionals, a thorough command of bond mechanics, yield calculations, credit analysis, the price-yield relationship, the effects of interest rate changes on bond prices, and the regulatory framework governing bond transactions is among the most critical bodies of knowledge in the entire licensing curriculum, featuring prominently on the SIE, Series 7, Series 63, Series 65, and Series 66 examinations.
This entry examines the definition and legal structure of a bond, the key terms embedded in every bond — coupon rate, par value, maturity, yield, and price — the four principal yield measures and how they differ, the foundational inverse relationship between bond prices and interest rates, the role of duration and convexity in measuring interest rate sensitivity, the major categories of bonds by issuer, the credit rating system and its investment grade and speculative grade designations, the bond indenture and trustee structure, the call provision and its implications, and the risks every bond investor bears.
A bond is a debt security representing a legally binding contractual obligation of the issuer to pay defined cash flows to the bondholder over the life of the instrument. The bond relationship is a creditor-debtor relationship — the bondholder is the creditor who has lent money to the issuer, and the issuer is the debtor obligated to make timely payments of interest and to repay principal at maturity.
This creditor relationship distinguishes bondholders from stockholders — stockholders are equity owners of the issuing company and bear residual risk, receiving returns only after all obligations to creditors are satisfied, while bondholders are creditors with contractual rights to defined payments that rank senior to equity claims.
The legal foundation of every bond is the bond indenture — a formal, detailed contract between the issuer and the bondholders, administered through a corporate trustee appointed to represent the bondholders' collective interests. The indenture specifies every material term of the bond obligation: the interest rate and payment schedule, the maturity date, the face value, any security or collateral backing the obligation, any call provisions allowing early redemption, any put provisions allowing the bondholder to demand early repayment, any sinking fund requirements mandating periodic principal retirement, financial covenants restricting the issuer's conduct during the bond's life, and the events of default that trigger the trustee's right to accelerate the entire outstanding principal balance. The trustee — typically a bank or trust company with no interest adverse to the bondholders — monitors the issuer's compliance with all indenture terms and takes action on behalf of the bondholder class when violations occur.
Understanding bonds requires precise command of the specific terminology that defines each instrument's cash flows and market behaviour.
The par value — also called the face value, nominal value, or principal amount — is the dollar amount the issuer must repay to the bondholder at maturity. It is the amount that was originally borrowed. For corporate and Treasury bonds, par value is typically one thousand dollars per bond.
For municipal bonds, par value is also typically one thousand dollars, though some municipal issues use five thousand dollar or other denominations. The par value is the baseline around which all price and yield calculations are structured.
A bond's market price is expressed as a percentage of par value. A bond quoted at one hundred is trading at par — at exactly one hundred percent of its face value. A bond quoted at ninety-five is trading at a five percent discount — at ninety-five percent of par, or nine hundred and fifty dollars for a one thousand dollar bond. A bond quoted at one hundred and five is trading at a five percent premium — at one hundred and five percent of par, or one thousand and fifty dollars.
The coupon rate — also called the nominal rate, stated rate, or contract rate — is the annual interest rate specified in the bond indenture, expressed as a percentage of par value. It is set at issuance and does not change over the life of a fixed-rate bond.
A bond with a par value of one thousand dollars and a coupon rate of five percent pays fifty dollars in annual interest — typically divided into two semiannual payments of twenty-five dollars each, paid every six months on the dates specified in the indenture.
The term coupon derives from the historical practice of bearer bonds, which had physical coupons attached to the certificate that the bondholder clipped and presented to the paying agent to collect each interest payment.
The coupon rate is set at issuance to reflect the prevailing market interest rate environment for that type of issuer and maturity, adjusted for the issuer's credit risk.
A highly creditworthy issuer such as the United States Treasury can borrow at lower coupon rates than a corporation of moderate credit quality, which in turn borrows at lower rates than a speculative-grade issuer. The coupon rate is the price the issuer pays to borrow money — its cost of debt capital.
The maturity date is the specific future date on which the issuer is contractually obligated to repay the par value to the bondholder. Bonds are broadly classified by maturity into three duration categories. Short-term bonds — sometimes called notes or bills — mature within one to three years of issuance, though the term money market security applies to instruments with original maturities of one year or less. Intermediate-term bonds mature in three to ten years. Long-term bonds mature in ten years or more, with thirty-year bonds and even longer maturities issued by certain issuers including the United States Treasury, which issues thirty-year bonds as one of its benchmark instruments.
The maturity of a bond is the most important determinant of its sensitivity to changes in market interest rates. Longer-maturity bonds have substantially greater price sensitivity to interest rate changes than shorter-maturity bonds, because they commit the bondholder to receiving the fixed coupon rate for a longer period during which market rates may change dramatically.
Yield is the annual rate of return earned by an investor on a bond investment, expressed as a percentage. Because bonds trade at prices that may differ from their par value, yield differs from the stated coupon rate whenever the bond's price is above or below par. Four distinct yield measures are tested extensively on securities licensing examinations, each serving a different analytical purpose.
The coupon yield — identical to the coupon rate or nominal rate — is simply the annual interest payment divided by the par value. For a five percent bond with a one thousand dollar par value, the coupon yield is five percent regardless of the bond's market price. The coupon yield never changes over the life of the bond because neither the annual coupon payment nor the par value changes.
The current yield is the annual coupon payment divided by the bond's current market price — the yield an investor receives relative to what they pay for the bond in the market today. If a five percent coupon bond with a one thousand dollar par value is currently trading at nine hundred dollars, the current yield is fifty dollars divided by nine hundred dollars, which equals five point five six percent — higher than the coupon rate because the investor is paying less than par value but still receiving the full fifty dollar annual coupon. If the same bond trades at eleven hundred dollars, the current yield is fifty dollars divided by eleven hundred dollars, which equals four point five five percent — lower than the coupon rate because the investor pays more than par but still receives only the fixed fifty dollar coupon.
The current yield reflects the income return component of bond investment but ignores the capital gain or loss that arises from the difference between the purchase price and the par value repaid at maturity. An investor who buys a bond at nine hundred dollars will receive one thousand dollars at maturity — a capital gain of one hundred dollars that the current yield does not capture.
Yield to maturity — abbreviated YTM and confirmed by FINRA as the most important yield measure for bond investment analysis — is the total annual return earned by an investor who purchases the bond at its current market price and holds it to maturity, assuming all coupon payments are received as scheduled and reinvested at the same yield. Mathematically, the yield to maturity is the discount rate that equates the present value of all future cash flows from the bond — all coupon payments plus the par value repayment at maturity — to the bond's current market price.
For a bond trading at a discount below par, the yield to maturity is higher than both the coupon yield and the current yield, because it captures not only the coupon income but also the capital gain from buying below par and receiving par at maturity. For a bond trading at a premium above par, the yield to maturity is lower than both the coupon yield and the current yield, because it captures the capital loss from buying above par and receiving only par at maturity. For a bond trading at exactly par, the yield to maturity equals the coupon yield and the current yield.
The ranking of yield measures for bonds at a discount is: coupon yield is lowest, current yield is in the middle, and yield to maturity is highest. For bonds at a premium, the order reverses: yield to maturity is lowest, current yield is in the middle, and coupon yield is highest. This ranking — coupon, current, yield to maturity for discounts and yield to maturity, current, coupon for premiums — is among the most tested bond relationships on the Series 7 and Series 65 examinations.
Many bonds include call provisions allowing the issuer to redeem the bond before its stated maturity date. The yield to call is calculated identically to the yield to maturity, except that the assumed final cash flow occurs at the call date rather than the maturity date, and the assumed redemption amount is the call price rather than par value. When a bond is trading at a premium — which occurs when market interest rates are lower than the bond's coupon rate — it is in the issuer's interest to call the bond and refinance at lower rates, making the yield to call the more relevant yield measure for the investor.
Yield to worst is the lower of the yield to maturity and all yield to call calculations — the minimum yield an investor could receive assuming no default but assuming the issuer exercises whatever call option is most adverse to the bondholder. FINRA confirms that investors should know the yield to worst for every callable bond they hold or consider purchasing.
The most fundamental and most examination-tested principle of fixed income markets is the inverse relationship between bond prices and interest rates — the principle that when market interest rates rise, existing bond prices fall, and when market interest rates fall, existing bond prices rise. Understanding this relationship and the logic behind it is essential for every securities professional.
The inverse relationship arises from the fixed nature of the bond's coupon payment. Consider a bond with a five percent coupon rate and one thousand dollar par value, currently trading at par. This bond pays fifty dollars annually in interest. If market interest rates subsequently rise to six percent, a new one thousand dollar bond will pay sixty dollars annually. The existing five percent bond becomes less attractive — a rational investor would prefer to pay one thousand dollars for a new bond paying sixty dollars rather than the existing bond paying only fifty dollars. The price of the existing five percent bond must fall below one thousand dollars until its yield — accounting for both the fifty dollar coupon and the capital gain at maturity — equals six percent. Conversely, if market rates fall to four percent, new bonds pay only forty dollars, making the existing five percent bond more attractive, and its price will rise above par until its yield equals four percent.
This inverse relationship between price and yield is automatic, continuous, and universal — it applies to every fixed-rate bond in every market at all times. It creates the primary risk of fixed income investing for investors who may need to sell bonds before maturity.
Duration is the most important measure of a bond's price sensitivity to changes in interest rates — a single number that estimates how much a bond's price will change for a given change in yield. Duration is expressed in years and is conceptually the weighted average time until the investor receives the bond's cash flows, where each cash flow is weighted by its present value.
Modified duration is the most common form used for sensitivity analysis, expressing the approximate percentage change in bond price for a one percentage point — one hundred basis point — change in yield. A bond with a modified duration of seven will decline in price by approximately seven percent if yields rise by one percentage point, or increase in price by approximately seven percent if yields fall by one percentage point.
Duration increases with maturity — longer-maturity bonds have higher duration and are more sensitive to interest rate changes — and decreases with coupon rate — higher-coupon bonds return cash to investors sooner through larger coupon payments, reducing the average time until cash flows are received and therefore reducing sensitivity to rate changes. Zero-coupon bonds, which make no periodic interest payments and return all cash at maturity, have the highest duration of any bond — equal to their maturity — and therefore the greatest interest rate sensitivity.
Convexity is the measure of the non-linearity in the price-yield relationship — the fact that the price increase from a yield decline is greater than the price decrease from an equal yield increase. Positive convexity, which characterises most standard bonds, means the price-yield curve is concave up — it curves toward the investor, producing gains that exceed losses for equal yield movements in either direction. Convexity is a desirable property that increases with maturity and decreases with coupon rate.
The United States bond market encompasses four major categories of issuers, each with distinct risk characteristics, tax treatment, and regulatory oversight.
Treasury securities are debt obligations of the United States federal government, issued by the Department of the Treasury and backed by the full faith and credit of the United States. As the obligations of the world's largest economy and the issuer of the world's reserve currency, Treasury securities are universally regarded as free of default risk — they are the risk-free rate benchmark against which all other debt securities are priced. Treasury securities pay interest that is subject to federal income tax but exempt from state and local income taxes.
The Treasury market encompasses four instrument types distinguished by original maturity. Treasury bills are zero-coupon discount instruments with original maturities of four, eight, thirteen, seventeen, twenty-six, or fifty-two weeks, issued at a discount to face value and maturing at par with no periodic interest payments. Treasury notes are interest-bearing instruments with original maturities of two, three, five, seven, or ten years, paying semiannual coupons. Treasury bonds are long-term interest-bearing instruments with original maturities of twenty or thirty years, also paying semiannual coupons. Treasury Inflation-Protected Securities are notes and bonds whose principal adjusts periodically based on changes in the Consumer Price Index, protecting investors against inflation erosion.
Corporate bonds are debt securities issued by business entities — corporations, limited partnerships, and other private and public business organisations — to raise capital for business operations, capital expenditure, acquisitions, and refinancing. Corporate bonds are subject to federal, state, and local income taxes on their interest income. They carry credit risk — the risk that the issuer will default on interest or principal payments — that does not apply to Treasury securities, requiring a credit spread above the Treasury yield to compensate investors for bearing that risk.
Corporate bonds range across the full credit quality spectrum from the highest investment grade obligations of systemically important financial institutions and blue chip corporations to the deeply speculative issues of companies operating under financial distress. Investment grade corporate bonds — those rated Baa3 or above by Moody's and BBB minus or above by Standard and Poor's and Fitch — are characterised by strong capacity to meet financial commitments and are the appropriate fixed income investments for most conservative and moderate-risk portfolios. High yield bonds — those rated below investment grade, also called speculative grade or junk bonds — offer significantly higher coupon rates to compensate investors for their higher default risk but also carry substantially greater price volatility, credit risk, and default exposure.
Municipal bonds — commonly called munis — are debt securities issued by state governments, city and county governments, special-purpose government authorities, public school districts, transit systems, water authorities, and other governmental or quasi-governmental entities to finance public infrastructure, government operations, and capital projects. The defining tax characteristic of most municipal bonds is the exclusion of their interest income from federal income taxation under Internal Revenue Code Section 103, making them particularly valuable to investors in higher marginal income tax brackets for whom the after-tax yield of tax-exempt municipal bonds can exceed the after-tax yield of taxable alternatives paying nominally higher rates.
Municipal bonds are categorised as general obligation bonds — backed by the full faith, credit, and taxing power of the issuing governmental entity — and revenue bonds — backed solely by the specific revenue streams generated by the financed project, such as tolls, utility revenues, hospital receipts, or student loan repayments. General obligation bonds typically carry lower credit risk than revenue bonds because they are backed by the broad taxing power of the government, though the credit quality of both types varies significantly across issuers.
Interest on certain municipal bonds — particularly private activity bonds whose proceeds are used for private rather than governmental purposes — is subject to the Alternative Minimum Tax preference item rules under IRC Section 57, making these bonds less advantageous for investors subject to the Alternative Minimum Tax than standard governmental obligation municipals.
Agency securities are debt obligations of federal government agencies — primarily Ginnie Mae, backed by the full faith and credit of the United States — and government-sponsored enterprises including Fannie Mae, Freddie Mac, the Federal Home Loan Banks, and the Federal Farm Credit Banks. Agency securities carry either explicit government backing or the implicit assumption of government support and therefore trade at yields only modestly above comparable Treasury yields. Interest on agency securities issued by Federal Home Loan Banks and Federal Farm Credit Banks is exempt from state and local income taxes, while interest on Fannie Mae, Freddie Mac, and Ginnie Mae securities is subject to state and local taxes.
Credit rating agencies — primarily Moody's Investors Service, Standard and Poor's Global Ratings, and Fitch Ratings, each designated as a Nationally Recognised Statistical Rating Organisation by the SEC — assess the creditworthiness of bond issuers and individual bond issues, assigning ratings that express the agency's assessment of the probability of default and expected recovery in the event of default.
The rating scales differ modestly in notation across agencies but follow a common structure. The highest rating — triple-A — signifies exceptional financial strength and an extremely low probability of default. Ratings descend through double-A, single-A, and triple-B — all of which are investment grade ratings, signifying adequate to strong capacity to meet financial commitments with manageable default risk. The investment grade threshold — Baa3 at Moody's and BBB minus at Standard and Poor's and Fitch — is the dividing line that determines whether institutional investors such as pension funds, insurance companies, and bank trust departments may hold the securities under regulatory and fiduciary guidelines that restrict their fixed income portfolios to investment grade instruments.
Ratings below the investment grade threshold — Ba1 and below at Moody's, BB plus and below at S&P and Fitch — are speculative grade or high yield designations, carrying higher default risk and requiring higher yields to compensate investors for that risk. Bonds rated C or D are in or near default.
A bond downgraded from investment grade to below investment grade — a fallen angel — can experience dramatic price declines as institutional investors who are restricted to investment grade holdings are forced to sell, creating concentrated selling pressure regardless of market conditions.
Many bonds, particularly corporate and municipal bonds, include call provisions that grant the issuer the right to redeem the bond before its stated maturity date by paying the bondholders the specified call price — typically par value or a modest premium above par. Callable bonds give issuers the flexibility to refinance when market interest rates decline, allowing them to retire high-coupon debt and replace it with lower-coupon new bonds, reducing their interest expense.
For bondholders, call provisions create call risk — the risk that when market interest rates fall and the price of the bond rises above the call price, the issuer will exercise the call option and redeem the bond, forcing the investor to reinvest the returned principal in the lower prevailing rate environment at the moment when the bond's price appreciation would otherwise have been greatest. Callable bonds compensate investors for accepting call risk by offering higher coupon rates than comparable non-callable bonds — the yield premium above non-callable equivalents is often described as the option-adjusted spread that prices the value of the issuer's embedded call option.
Beyond credit risk and interest rate risk — the two risks most intensively examined in the licensing curriculum — bond investors bear several additional risk categories that registered representatives and investment advisers must understand and communicate clearly.
Reinvestment risk is the possibility that coupon payments received over the bond's life will be reinvested at lower yields than the yield to maturity assumed at purchase. Because yield to maturity assumes reinvestment of all coupon payments at the yield to maturity rate, if actual reinvestment rates are lower — as occurs during periods of declining interest rates — the actual total return will be less than the projected yield to maturity.
Inflation risk is the possibility that the bond's fixed interest payments will lose real purchasing power if the inflation rate rises above the coupon rate, leaving the investor with a negative real return despite receiving promised nominal cash flows. Treasury Inflation-Protected Securities directly address inflation risk by adjusting principal for inflation.
Liquidity risk is the possibility of being unable to sell a bond in the secondary market at a fair price, particularly for thinly traded corporate or municipal bonds where the bid-ask spread is wide and buyer interest is limited.
Default risk is the risk that the issuer will fail to make scheduled interest or principal payments, producing a loss of income and potentially a loss of principal. Default risk is the primary determinant of the credit spread — the yield premium above the risk-free Treasury rate that compensates bondholders for bearing this risk.
Event risk encompasses unexpected developments — hostile takeovers, natural disasters, regulatory actions, or major litigation — that rapidly and adversely change the issuer's credit profile, often triggering bond price declines that occur too suddenly for investors to exit positions at pre-event prices.
Bonds are the single most extensively tested category of investment instruments across the SIE, Series 7, and Series 65 examinations — covering the full range of concepts from basic terminology through advanced yield calculations, price-yield relationships, duration, credit analysis, and specific bond types. Candidates must command every concept in this entry with precision.
The core points to retain are these: a bond is a debt security representing a loan from the bondholder to the issuer, obligating the issuer to pay periodic interest at the coupon rate and to repay par value at maturity, with the bondholder holding a creditor claim senior to equity in the capital structure; key terms are par value — the face amount repaid at maturity, typically one thousand dollars — the coupon rate — the fixed annual interest rate expressed as a percentage of par — and maturity date — the date on which par value is repaid; the four yield measures are coupon yield equalling annual coupon divided by par, current yield equalling annual coupon divided by current market price, yield to maturity equalling the total annualised return to maturity accounting for price-par difference and coupon income, and yield to call equalling the same calculation to the first call date at the call price; for discount bonds the yield ranking is coupon yield below current yield below yield to maturity, and for premium bonds the order reverses; bond prices and yields move inversely — when market rates rise bond prices fall, and when rates fall prices rise — because the fixed coupon becomes relatively less or more attractive than current market rates; duration measures percentage price change per one percentage point yield change, increases with maturity and decreases with coupon rate, and is highest for zero-coupon bonds; investment grade bonds are rated Baa3 or above by Moody's and BBB minus or above by S&P and Fitch while below those thresholds are high yield or junk bonds; Treasury bonds carry no default risk and pay interest exempt from state taxes, corporate bonds are fully taxable, and most municipal bonds pay interest exempt from federal income tax under IRC Section 103; and call provisions allow issuers to redeem bonds before maturity — creating call risk for investors that is compensated through higher initial yields on callable versus non-callable bonds.
