On the validity of the weak-form efficient markets hypothesis applied to the London stock exchange

Abstract

The validity of the weak form of the efficient markets hypothesis (EMH) is tested for the FTSE 30 share index during a period when government economic policy towards the financial markets was relatively unchanging. The EMH would suggest random walk behaviour but this does not occur; instead the data series has significant heteroscedasticity. The series is successfully explained by a GARCH M(1, 1) model. We use the BDS test to show that the residuals from this model are IID.