Growth, debt and cost of capital: Italy, Germany and the United States (20002024)

This paper compares Italy, Germany and the United States over the period 2000–2024, focusing on real growth, public debt dynamics and the cost of capital. The analysis constructs an operational measure of “net” GDP by subtracting consumption taxes and expressing 2024 values in 2000 prices through cumulative inflation factors. The results highlight a marked divergence: Italy shows substantially zero real growth, despite prolonged primary fiscal discipline; Germany records moderate real growth with a lower debt-servicing burden; the United States records stronger real growth while maintaining a comparatively contained cost of public debt. The paper discusses the role of the interest rate–growth differential (r–g), the cumulative macroeconomic effects of persistent differences in interest expenditure, and the institutional framework of the euro area as a possible explanation for long-term divergence in public capital costs and growth outcomes. The study is intended as a numerical and theoretical contribution to the debate on fiscal discipline, debt sustainability, monetary architecture and macroeconomic stabilization.