What is the foundation of solid financial architecture? How is it possible to prevent a constant increase in taxes, debts and the misallocation of financial resources? The theory of institutional congruence provides a clear answer: The circles of decision makers, beneficiaries and payers must overlap to the greatest possible extent. This requires the consistent institutional centralisation or decentralisation of power and responsibilities regarding taxes, expenditure and debts. This study’s analysis of sovereign and subnational public entities in the eurozone, Germany, France, Canada, the USA and Switzerland as well as of debt crises among autonomous sovereign debtors shows how the implementation of institutional congruence works in practice.