Long-Term Asset Price Volatility and Macroeconomics Fluctations

We analyze a stochastic growth model with lags in the operation of new technologies. Stock values are impacted by news on technological innovations and some other external shocks affecting the economy. Episodes of technology adoption may generate long fluctuations in the aggregate value of stocks. We asses the quantitative importance of various macroeconomic variables in accounting for both the observed volatility of stock values and the less pronounced volatility of real macroeconomic aggregates. Our analysis singles out price markups and leverage as key determinants of asset price volatility, and confers a rather limited role to adjustment costs, taxes, and labor and financial frictions.