Coterminous debt

Coterminous debt arises when separate governmental units share exactly the same geographic boundaries and each issues its own debt. A city and a school district that cover precisely the same territory are coterminous — every property owner inside the line is taxed by both entities, so both bond issues ultimately rest on the same tax base.

This matters because a municipality's own balance sheet understates what its taxpayers actually owe. Direct debt is what the issuer borrowed itself. Overlapping debt is the share of debt issued by other units that the issuer's taxpayers are also responsible for. Coterminous debt is the simplest case of overlapping debt: because the boundaries match perfectly, 100% of the other unit's debt is attributed to the same taxpayers rather than an apportioned fraction. Direct debt plus overlapping debt equals net overall debt, the figure analysts compare against property values and population.

Analysts use overall debt to compute ratios such as debt per capita and debt to assessed valuation. A city that looks conservatively financed on its own can carry a heavy combined burden once a coterminous school district's bonds are counted, and rating agencies weigh that combined figure when assessing repayment capacity.

Coterminous and overlapping debt appear in the municipal securities portion of the Series 7 exam, within the analysis of general obligation bonds. Know that GO bonds are backed by taxing power, that overlapping debt must be added to direct debt to judge the true burden on taxpayers, and that coterminous units share boundaries so their debt is counted in full.