Public Purpose Bond

Most muni bonds at least pretend to be of this flavor. They're doing something good-ish for the public. That parking structure? Good. That new park development with slides and swings, without heroin needles buried in the sand? Good. That bridge over troubled waters? Good in the original version from 1978, anyway.

The bonds attract investors out of a kind of do-gooder "obligation" to fund them. They typically pay low-ish interest rates and have a few big backers, often one or two of them planning to run for mayor at some point thereafter.

This is a vastly different bond from a public porpoise bond, which is really just, um...a red herring.