Considerable attention has been given in the financial press to the increase in stock market volatility during the late 1990s. The facts suggest, however, that this attention has been misplaced. As shown first by Schwert (1989), no long-run uptrend is evident for the volatility of the market as a whole. The volatility of the market during the late 1990s, while larger than it was earlier in the decade, was still considerably below the volatility recorded during earlier periods of the century.
What has received far less attention is the behavior of the volatility of individual stocks. The volatility of individual stocks can increase even when the volatility of the market as a whole remains stable as long as correlations among stocks are declining. In this study, we show, from a different perspective and using different measures from those used by Campbell, Lettau, Malkiel, and Xu (2001), that volatilities of individual stocks have indeed increased over the decades of the 1980s and 1990s. When the total volatility of individual stocks is decomposed into systematic volatility and idiosyncratic volatility, we present clear evidence that idiosyncratic volatility has trended up. We find that our result is not solely attributable to the increasing prominence of the NASDAQ market. Most importantly, we find from cross-sectional regressions that the volatility of individual stocks may be related to the amount of institutional ownership and to the firms’ objectives in pursuing high growth.