economics Paradigm Challenge

A city's lack of industrial diversity only hurts its credit rating if the city is already poor.

March 31, 2026

Original Paper

Industrial Concentration, Property Values, and Municipal Bond Spreads

Kenneth Robinson Ahern

SSRN · 6471598

The Takeaway

Standard economic wisdom says cities should diversify their industries to lower risk. However, this study found that municipal bond markets only penalize 'one-company towns' if property values are low; wealthy cities can remain highly concentrated in a single industry without facing higher borrowing costs.

From the abstract

This paper proposes that the composition of a city's industrial base helps determine the pricing of its bonds through the interaction of two channels. First, cities that are home to a diversified set of industries can better absorb shocks to any single sector. Second, cities dominated by high-wage industries are more affluent and have greater fiscal capacity to absorb shocks. Using a panel of 1,253 cities from 2005 to 2022, I show that employment concentration raises municipal bond spreads but o