بررسی مجدد شرکت، صنعت و نوسانات بازار

In updating Campbell et al. (2001) we find evidence that the level of idiosyncratic volatility, industry-specific volatility, and market volatility have increased to their highest levels in 50 years during the 21st century. Our findings show that while the 2007–2008 Financial Crisis led to large spikes in all three measures of volatility, the Tech Bubble of early 2000’s led to an even greater increase in firm and industry volatilities than the Financial Crisis. By 2010, volatilities mostly returned to their pre-crisis levels. We also find evidence that the average correlation among stocks, which decreased during 1960–2000 period, has been increasing steadily since early 2000’s.