Abstract

This article presents statistics on the changes in the structure of the mutual building society industry in the United Kingdom from 1983 to 1992. Measures of absolute and relative concentration are computed and it is shown that while the industry has experienced an increase in absolute concentration, relative concentration has decreased. Two measures of firm stability are also computed and it is shown that with the effects of mergers excluded, there has been an increase in market share and ranking instability. The study ends with a brief discussion of the relationship between concentration and stability in the context of the mutual building society industry.