A Tale of Two Margins: Monetary Policy and Capital Misallocation

This paper investigates the impact of monetary policy on capital misallocation, focusing on its heterogeneous effects on firms. Using Spanish firm-level data spanning 1999 to 2019, we demonstrate that expansionary monetary policy leads to a reduction in capital misallocation, measured by the within-industry dispersion of firms’ marginal revenue product of capital (MRPK). To analyze the underlying mechanism, we first examine the intensive margin and find that high-MRPK firms exhibit a greater increase in investment and debt financing relative to low-MRPK firms following a monetary policy easing surprise. We also find that a firm’s MRPK serves as a stronger determinant of its investment sensitivity to monetary policy than factors such as age, leverage, or cash, suggesting that MRPK is a reliable proxy for financial frictions. Next, we explore the extensive margin and demonstrate that monetary policy easing stimulates entry and discourages exit, although the quantitative impact is small. Moreover, we find no significant changes in the composition of high- and low-MRPK entrants or exiters. Overall, our findings suggest that expansionary monetary policy primarily reduces capital misallocation by alleviating financial frictions among incumbent productive and constrained firms.