Why Does Stock Volatility Change Over Time?


G. William Schwert

University of Rochester, Rochester, NY 14627
and National Bureau of Economic Research


Journal of Finance, 44 (December 1989) 1115-1153


This paper analyzes the relation of stock volatility with real and nominal macroeconomic volatility, financial leverage, stock trading activity, default risk, and firm profitability using monthly data from 1857-1986. An important fact, previously noted by Officer[1973], is that stock return variability was unusually high during the 1929-1940 Great Depression. Moreover, leverage has a relatively small effect on stock volatility. The amplitude of the fluctuations in aggregate stock volatility is difficult to explain using simple models of stock valuation.

Key words: Stock Market, Volatility, Inflation, Interest Rates, Leverage, Diversification, ARIMA

JEL Classifications: G12, G14, E32


Cited 117 times in the SSCI through April 1996

© Copyright 1989, American Finance Association
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