Municipal bond

A municipal bond, often called a “muni,” is a debt security issued by a U.S. state or local government, public authority, or other eligible public entity. The issuer borrows money from bondholders, generally to finance public infrastructure, services, or other obligations, and promises repayment under the bond’s terms. Municipal bonds vary in their repayment pledges, maturity, interest structure, and federal and state tax treatment. ^[1][2]

Purpose and basic structure

Municipalities and public authorities use borrowing to help fund projects and obligations that may require substantial capital. Examples include schools, highways, sewer systems, hospitals, airports, bridges, and utilities. Borrowing may also support an issuer’s day-to-day obligations. The bond is a contractual obligation: the entity responsible for repayment agrees to make interest payments and return principal according to the security’s terms. ^[1][2]

A bond’s **principal**, also called its face value or par value, is the amount due at maturity, subject to the terms of the issue. The **maturity date** is the date principal is scheduled to be repaid. Many municipal bonds pay interest periodically, often semi-annually, though the precise schedule and structure depend on the bond. Short-term municipal securities may mature in a few years; long-term bonds can remain outstanding for a decade or more. ^[2]

A municipal bond may be issued as part of a larger offering with multiple maturities, interest rates, and repayment terms. The offering’s official statement describes the security and its terms, including the issuer or obligated person, the pledged repayment source, maturity schedule, and material risks. MSRB guidance identifies the official statement as a key source for understanding a bond’s features. ^[6]

Main types and repayment pledges

The two broad categories most commonly discussed are general obligation bonds and revenue bonds. These labels describe different forms of repayment support, but do not by themselves establish the bond’s credit quality. The exact pledge and applicable state or local law matter. ^[1][3]

**General obligation bonds**, often abbreviated GO bonds, are backed by the issuer’s general credit and, depending on the bond and the issuer’s legal powers, taxing capacity. Repayment may come from general funds, income taxes, property taxes, or appropriations. The source and priority of payment can vary across issuers. Some local GO bonds require voter approval before issuance, while requirements depend on the relevant jurisdiction and type of borrowing. ^[3]

**Revenue bonds** are payable from specified revenues rather than an issuer’s broad taxing power. The pledged source might be revenue generated by a financed facility, such as tolls, water and sewer charges, airport fees, or utility receipts; it can also include specified taxes, grants, or other legally pledged revenues. Bondholders’ rights generally depend on the particular pledge. If the pledged source is inadequate, missed debt payments may result; revenue-bond holders generally cannot compel taxation or appropriations from sources that were not pledged. ^[1][3]

Some municipal bonds are issued through **conduit financing**. In that arrangement, a public entity issues bonds on behalf of a private or nonprofit borrower—for example, to finance a healthcare, housing, or educational facility. The borrower, often called the obligor, is responsible for repayment under the financing documents. The public entity’s role as issuer does not necessarily mean it guarantees payment if the borrower fails to pay. The specific documents determine the parties’ obligations. ^[1][2]

Municipal securities also differ in interest-rate structure. Many are fixed-rate bonds, with a stated rate that remains in place until maturity or earlier redemption. Variable-rate securities, including variable rate demand obligations, have interest rates that reset periodically; some combine long legal maturities with shorter rate-reset periods. ^[1]

Federal and state tax treatment

Interest on many municipal bonds is excluded from federal gross income, which is why these securities are often described as tax-exempt. The exemption is conditional: the issuer and bond must meet relevant federal tax-law requirements, and not every municipal bond receives the same treatment. Interest on some private activity bonds, for example, may be taxable, subject to statutory exceptions. Issuers have continuing compliance responsibilities in areas that include the use of bond proceeds and bond-financed property. ^[1][4][5]

Interest may also be exempt from state or local income taxes, often depending on the investor’s residence and the state or locality that issued the bond. The details vary, and exceptions apply. Tax treatment is therefore a characteristic of the specific security and investor circumstances, not an automatic feature of every bond issued by a government entity. ^[1][2]

Because tax-exempt interest may be more valuable to some investors than taxable interest, municipal bonds have often offered lower stated yields than otherwise comparable taxable fixed-income securities. Comparing a municipal bond’s yield with a taxable bond’s yield requires accounting for the investor’s applicable tax circumstances, as well as differences in credit, maturity, liquidity, and other terms. Tax status alone does not determine the security’s overall return or risk. ^[1][2][5]

Issuance, trading, and disclosure

Municipal bonds are sold in primary offerings and may subsequently trade in the secondary market. The official statement for a new issue provides offering information and key terms. After issuance, information about the security and its trading may be available through the Municipal Securities Rulemaking Board’s Electronic Municipal Market Access system, known as EMMA. ^[6][7]

EMMA provides free public access to municipal market information and disclosure documents. It is designated by the U.S. Securities and Exchange Commission as the official source for municipal securities data and disclosure documents. EMMA is an information resource, not a venue for purchasing or selling bonds. ^[7]

The municipal market has a distinct regulatory framework. The SEC administers federal rules relevant to municipal securities market participants, while the Municipal Securities Rulemaking Board (MSRB) develops rules for the municipal securities market under SEC oversight. The SEC’s Office of Municipal Securities coordinates SEC activities involving municipal market structure, disclosure, and municipal-advisor regulation. ^[8]

Risks and factors affecting value

Municipal bonds carry **credit risk**: the issuer or other obligated person may fail to pay interest or principal when due. Repayment depends on the bond’s specific pledge and the financial condition of the entity responsible for payment. Investors and analysts assess the security’s official statement and relevant financial and operating information rather than relying only on a general label such as “GO” or “revenue bond.” ^[3][9]

**Interest-rate risk** arises because a bond’s market price can change when market interest rates change. A bond with a fixed coupon may become less attractive relative to newly issued securities if market rates rise, putting downward pressure on its price; when rates fall, its price may rise. The extent of price sensitivity is influenced by factors such as maturity, coupon, and the bond’s terms. This market-price risk is distinct from whether the issuer ultimately makes all scheduled payments. ^[1][2]

**Liquidity risk** concerns how readily a bond can be sold at a price close to an estimated or recently observed value. Trading conditions and available price information may differ from those for frequently traded securities. Prices and yields can also reflect the security’s credit, maturity, call features, tax status, and the conditions of a particular transaction. MSRB investor materials direct readers to bond terms and trade-price information when researching municipal securities. ^[6][7]

Some bonds are **callable**, meaning the issuer may repay them before the stated maturity under specified conditions. A call can change the timing of an investor’s principal repayment and the period over which interest is received. Other bond-specific terms may also affect repayment rights and market value. These features are detailed in the official statement and related disclosure documents. ^[6][9]

Credit ratings, where available, are one source of information about an issuer’s or bond’s creditworthiness, but they do not guarantee repayment or replace analysis of the bond’s specific terms. The SEC has cautioned that credit analysis should identify who is responsible for payment and consider that entity’s financial condition, including the security’s actual repayment source. ^[9]

Municipal bonds and investors

Investors can hold individual municipal bonds directly or gain exposure through pooled investments, such as mutual funds and exchange-traded funds that invest in municipal securities. A bond fund generally holds a portfolio rather than promising repayment of principal on a particular date for each fund investor; its value reflects the portfolio and fund structure. The method of exposure therefore affects how an investor experiences maturity, diversification, and market-price changes. ^[1][6]

A municipal bond’s tax treatment, repayment pledge, maturity, interest structure, and liquidity are separate characteristics. For example, a bond can be issued by a government entity but repayable from a narrow revenue stream, or it can be issued as a conduit financing for which a private borrower is the principal obligor. Evaluating the security requires distinguishing the issuer from the entity responsible for repayment and reading the terms that define the pledge. ^[3][9]

Related concepts

Municipal bonds are one part of the broader fixed-income market and a financing channel for U.S. state and local government activity. The U.S. Census Bureau collects comprehensive state and local government finance data, including information on debt, that can be used to study government finances at an aggregate level. Such government-level debt statistics are not a substitute for the terms or disclosure of an individual bond issue. ^[10]