Municipal Bond - Risk

Risk

The risk ("security") of a municipal bond is a measure of how likely the issuer is to make all payments, on time and in full, as promised in the agreement between the issuer and bond holder (the "bond documents"). Different types of bonds are secured by various types of repayment sources, based on the promises made in the bond documents:

• General obligation bonds promise to repay based on the full faith and credit of the issuer; these bonds are typically considered the most secure type of municipal bond, and therefore carry the lowest interest rate.
• Revenue bonds promise repayment from a specified stream of future income, such as income generated by a water utility from payments by customers.
• Assessment bonds promise repayment based on property tax assessments of properties located within the issuer's boundaries.

In addition, there are several other types of municipal bonds with different promises of security.

The probability of repayment as promised is often determined by an independent reviewer, or "rating agency". The three main rating agencies for municipal bonds in the United States are Standard & Poor's, Moody's, and Fitch. These agencies can be hired by the issuer to assign a bond rating, which is valuable information to potential bond holders that helps sell bonds on the primary market.

Municipal bonds have traditionally had very low rates of default as they are backed either by revenue from public utilities (revenue bonds), or state and local government power to tax (general obligation bonds). However, sharp drops in property valuations resulting from the 2009 mortgage crisis have led to strained state and local finances, potentially leading to municipal defaults. For example, Harrisburg, PA, when faced with falling revenues, skipped several bond payments on a municipal waste to energy incinerator and did not budget more than $68m for obligations related to this public utility. The prospect of Chapter 9 municipal bankruptcy was raised by the Controller of Harrisburg, although it was opposed by Harrisburg's mayor.