We test for a change in the volatility of 215 US macroeconomic time series over the period 1960-1996. We find that … about 90\\% of these series have experienced a break in volatility during this period. This result is robust to controlling … for instability in the mean and business cycle nonlinearities. Real variables have seen a reduction in volatility since …

Volatility breaks are tested and documented for 19 important monthly macroeconomic time series across the G7 countries … structural break, volatility breaks are found to be widespread. This continues to hold when business cycle nonlinearities are … allowed in the variance. Multiple volatility breaks are also examined, and these are found to be especially prevalent for …