Stock prices should respond only to unpredictable components of economic news ('innovations') in efficient markets. While innovations used in empirical investigations of the economic underpinnings of stock market risk should at least satisfy this basic requirement, this may not guarantee...

This study investigates multiple changes in persistence in the dividend–price and price–earnings ratio of the NASDAQ Composite Index. Recent time series methods that are capable of signalling and dating asset price bubbles are employed, in particular the method developed by Leybourne, Kim,...