Capital Unemployment

This paper studies the unemployment of physical capital—defined as idle units searching to be traded—and its macroeconomic implications. I provide evidence documenting that capital unemployment is large, volatile, and increases during economic downturns. I construct a capital-accumulation model that explains these patterns, with trading frictions in capital markets, which give rise to equilibrium capital unemployment, and financial shocks, which lead to large fluctuations in trading probabilities and capital unemployment. Using the model, I show that trading frictions and capital unemployment matter for aggregate dynamics. First, unemployed capital affects aggregate investment dynamics: Downturns characterized by large increases in unemployed capital are followed by investment slumps, because the economy tends to recover by absorbing existing unemployed capital rather than by producing new capital goods. Second, capital unemployment constitutes a propagation mechanism from financial shocks to economic activity, which shows up at the aggregate level as measured total factor productivity.