Inelastic Demand Meets Optimal Supply of Risky Sovereign Bonds

We present evidence of inelastic demand for risky sovereign bonds and explore its implications for optimal government debt policies. Using monthly changes in the composition of a major international bond index, we identify flow shocks unrelated to fundamentals that shift the available bond supply. From these shocks, we estimate an inverse demand elasticity of -0.30 and show that it increases with countries’ default risk. We formulate a sovereign debt model with endogenous default and inelastic investors, calibrated to our empirical estimates. By penalizing additional borrowing, an inelastic demand acts as a disciplining device that reduces default risk and bond spreads.