Definition: Volatility clustering is as follows: In a time series of stock prices, it is observed that the variance of returns or log-prices is high for extended periods and then low for extended periods.
(E.g. the variance of daily returns can be high one month and low the next.)
This occurs to a degree that makes an iid model of log-prices or
returns unconvincing. This property of time series of prices can be called
'volatility clustering' and is usually approached by modeling the price
process with an ARCH-type model.
Terms related to Volatility Clustering:
About.Com Resources on Volatility Clustering:- How Stock Prices Are Determined
- Do Changes in Stock Prices Cause Recessions?
- When Stock Prices Go Down, Where Does the Money Go?
Books on Volatility Clustering:
Journal Articles on Volatility Clustering:
