On the Value of Municipal Bond Insurance: An Empirical Analysis

Using a large sample of municipal bond data from 2001 to 2010 in the U.S., this paper documents the time variation of the value of municipal bond insurance, estimated from the insured and uninsured bonds yield at issue differentials. We find that insured municipal bonds carry significant lower yields at issue compared to those of the equivalent uninsured bonds before 2008. However, this cost saving disappeared with the aftermath of the subprime credit crisis. We find that the supply of bonds and the level of market interest rates to have significant positive impacts on the time-varying value of bond insurance. We also detect asymmetric response of these yield differentials to rises and declines of market interest rates. Economic intuition suggests that the value of municipal bond insurance is a function of business cycles but our tests support the contrary, which may be explained by the habitat preference of municipal bonds issues.