Stablecoins Meet the Mundell–Fleming Trilemma

We study how stablecoins impact global capital flows by constructing a novel wallet-level dataset linking geotagged Ethereum Name Service registrations to stablecoin transactions around banking restrictions, currency crises, sanctions, and monetary disruptions. We find that crisis-country wallets experience significant increases in USD stablecoin inflows and receipt activity during crisis weeks. Motivated by this evidence, we develop a small-open-economy New Keynesian model in which household adoption of programmable stablecoins weakens the government’s enforcement technology for capital controls by making capital mobility endogenous. The empirical evidence validates the model’s central assumption that flight pressure increases stablecoin adoption. Stablecoins therefore tighten the Mundell–Fleming trilemma by reducing the government’s ability to sustain independent monetary policy under a fixed exchange-rate regime.