We show that an increase in aggregate uncertainty-measured by stock market volatility-reduces productivity growth more in industries that depend heavily on external finance. This effect is larger during recessions, when financing constraints are more likely to be binding, than during expansions....

Fund models are statistical descriptions of markets where all asset returns are spanned by the returns of a lower-dimensional collection of funds, modulo orthogonal noise. Equivalently, they may be characterised as models where the global growth-optimal portfolio only involves investment in the...