Municipal securities consist of both short-term issues (often called notes, which typically mature in one year or less) and long-term issues (commonly known as bonds, which mature in more than one year). Short-term notes are used by an issuer to raise money for a variety of reasons: in anticipation of future revenues such as taxes, state or federal aid payments, and future bond issuances; to cover irregular cash flows; meet unanticipated deficits; and raise immediate capital for projects until long-term financing can be arranged. Bonds are usually sold to finance capital projects over the longer term.

The two basic types of municipal bonds are:

General obligation bonds. Principal and interest are secured by the full faith and credit of the issuer and usually supported by either the issuer’s unlimited or limited taxing power. In many cases, general obligation bonds are voter-approved.

Revenue bonds. Principal and interest are secured by revenues derived from tolls, charges or rents from the facility built with the proceeds of the bond issue. Public projects financed by revenue bonds include toll roads, bridges, airports, water and sewage treatment facilities, hospitals and subsidized housing. Many of these bonds are issued by special authorities created for that particular purpose.

Certificates of Participation.  It may be possible to fund a municipal project without going to the voters by issuing certificates of participation (or a lease purchase). 

Minimum investment. Most municipal notes and bonds are issued in minimum denominations of $5,000 or multiples of $5,000.

Municipal bond issuers

Municipal bonds are issued by states, cities, and counties, (the municipal issuer) to raise funds. The methods and traces of issuing debt are governed by an extensive system of laws and regulations, which vary by state. Bonds bear interest at either a fixed or variable rate of interest, which can be subject to a cap known as the maximum legal limit. If a bond measure is proposed in a local county election, a Tax Rate Statement may be provided to voters, detailing best estimates of the tax rate required to levy and fund the bond.

The issuer of a municipal bond receives a cash payment at the time of issuance in exchange for a promise to repay the investors who provide the cash payment (the bond holder) over time. Repayment periods can be as short as a few months (although this is rare) to 20, 30, or 40 years, or even longer.

The issuer typically uses proceeds from a bond sale to pay for capital projects or for other purposes it cannot or does not desire to pay for immediately with funds on hand. Tax regulations governing municipal bonds generally require all money raised by a bond sale to be spent on one-time capital projects within three to five years of issuance. Certain exceptions permit the issuance of bonds to fund other items, including ongoing operations and maintenance expenses, the purchase of single-family and multi-family mortgages, and the funding of student loans, among many other things.

Because of the special tax-exempt status of most municipal bonds, investors usually accept lower interest payments than on other types of borrowing (assuming comparable risk). This makes the issuance of bonds an attractive source of financing to many municipal entities, as the borrowing rate available in the open market is frequently lower than what is available through other borrowing channels.

Municipal bonds are one of several ways states, cities and counties can issue debt. Other mechanisms include certificates of participation and lease-buyback agreements. While these methods of borrowing differ in legal structure, they are similar to the municipal bonds described in this article..

Municipal bond holders

Municipal bond holders may purchase bonds either directly from the issuer at the time of issuance (on the primary market), or from other bond holders at some time after issuance (on the secondary market). In exchange for an upfront investment of capital, the bond holder receives payments over time composed of interest on the invested principal, and a return of the invested principal itself (see bond).

Repayment schedules differ with the type of bond issued. Municipal bonds typically pay interest semi-annually. Shorter term bonds generally pay interest only until maturity; longer term bonds generally are amortized through annual principal payments. Longer and shorter term bonds are often combined together in a single issue that requires the issuer to make approximately level annual payments of interest and principal. Certain bonds, known as zero coupon or capital appreciation bonds, accrue interest until maturity at which time both interest and principal become due.