External Financing and the Role of Financial Frictions over the Business Cycle: Measurement and Theory

We examine the quantitative importance of financial market shocks in accounting for business cycle fluctuations. We emphasize the role financial markets play in reallocating funds from cash-rich, low productivity firms to cash-poor, high productivity firms. We use evidence on financial flows to analyze the importance of this role of financial markets. This evidence shows that in the aggregate, funds available to firms internally are more than adequate to finance investment. At the firm level, we find that for publicly traded firms (in Compustat), almost all investment is financed internally while, using a alternative data source (Amadeus), we find that most investment by privately held firms is financed through borrowing. These observations suggest that the quantitative impact of financial market shocks depend both on the sensitivity of investment and output of privately held firms to such shocks and on the extent to which the investment and output of publicly held firms respond to the actions of privately held firms. Motivated by these observations, we build a quantitative model featuring publicly and privately held firms that face collateral constraints and idiosyncratic risk over productivity. We model financial market shocks as shocks to the collateral constraints. In our model, each firm has a monopoly in producing a differentiated good and uses the goods produced by other firms as an input for production -- features that create non-financial linkages between publicly and privately held firms. In our calibrated model, we find that a shock to the collateral constraints which generates a one standard deviation decline in the debt-to-asset ratio leads to a 0.5% decline in aggregate output on impact, roughly comparable to the effect of a one standard deviation shock to aggregate productivity in a standard real business cycle model. In this sense, we find that disturbances in financial markets are a promising source of business cycle fluctuations when non-financial linkages across firms are sufficiently strong.