The essence, genesis, effectiveness, constraints and implications of economic structure transformation are some of the most important, and at the same time most complex and controversial, issues the economic sciences deal with. These issues are also permanently topical, since there is a continuous process going on, in which some parts of the economic structure disappear, whilst the remaining ones are updated and new elements arise. Structural changes in the banking sector and banking organisations have been attracting interest from both the economic science and business practice in well-developed countries for many years now. This interest is shown through the vast amount of academic literature on the one hand and numerous studies and reports published by various banks and other financial institutions on the other hand. Those publications repeatedly mention structure diversification in the banking sector and banking organisations.

This paper mainly aims for theoretical explanation of the structure diversification processes in the banking sector and banking organisations. The point is to show the nature, genesis, components, barriers, constraints and implications of those processes. The purpose of writing this paper is both to outline the structure diversification theory and to form some opinions and conclusions which may be found useful in the economic policy (specifically: in the banking policy). The central idea of this paper is to try and discover the essence, which often differs from the external form, of the structure diversification phenomena in the banking sector and banking organisations. In case of Poland, banking diversification is undoubtedly in statu nascendi. It seems interesting, probably not only for general cognition reasons, to try and find out to what extent the processes which have been going on in Poland in the recent years (1989-1999) have been objective and to what extent they have resulted merely from a set of specific factors and circumstances.

This paper is, inter alia, an attempt to present a logical review of a research hypothesis on the possibility to optimise the method of combining the advantages of specialised banking organisations and the advantages of universal ones. In other words, the point is to develop a model of a flexible bank, which is diversified and, at the same time, specialised. The challenge and inspiration to search for some kind of modus vivendi was the famous general opinion expressed by P.F. Drucker, the modern management guru, in his book Effective Management: 'When separate from each other, specialisation and diversification are not likely to be effective.' In another perspective, the point is to strike a balance between 'underdiversification' and 'overdiversification' (offering 'everything for everybody').