Capital Share Risk

This article surveys evidence on the evolution of the capital share—the portion of output accruing to firm owners as after-tax profits—and its contribution to asset prices, arguing that capital share risk is a dominant driver of equity values. Using aggregate data on the US corporate sector, we show that the capital share has more than doubled since the late 1980s, driven primarily by a falling labor share. These changes have passed through nearly one-for-one into higher corporate payouts and help explain the long-run divergence between growth in the value of the stock market and real economic activity. Our review summarizes existing research on the measurement and structural consequences of movements in the capital share and outlines open questions about its empirical properties and endogenous links to macroeconomic variables. In sum, capital share risk is essential to understanding asset pricing dynamics in the modern economy.