We show that firms' idiosyncratic volatility in returns and cash flows obeys a strong factor structure. We find that the stocks of firms with large, negative common idiosyncratic volatility (CIV) factor betas earn high average returns. The CIV beta quintile spread is 6.4% per year. To explain...

We propose a network model of firm volatility in which the customers' growth rate shocks influence the growth rates of their suppliers, larger suppliers have more customers, and the strength of a customer-supplier link depends on the size of the customer firm. Even though all shocks are i.i.d.,...