This article presents interview results which are part of a wider research programme into the control bank managers have of their banks' return generating resources (captured as core capabilities). In particular, changes in growth opportunities within bank markets emerging from regulatory change and IT innovations are explored through banks' geographic, product market, and customer group diversification strategies within three competitive environments (i.e. UK, Mexico and Spain). Research hypothesis were investigated through a total of 55, 1- hour, semi-structured interviews with managers of commercial banks, investment banks, management consulting firms and regulators from Mexico, Spain and the United Kingdom. Qualitative and quantitative analysis of this set of data suggested that domnestic competitors rather than foreign banks were perceived as the top driver for change of industrial boundaries. IT management played a secondary role in the design of bank strategy but at the same time, was perceived as an important force of change in bank markets. The great majority of banks reckined responding to changes in their growth opportunities through changes in their diversification moves and building upon a platform- based view of core capabilties. The article is divided in two parts. Part one presents a framework to analyse the relationship between core capabilities and diversification moves. Part two relates this framework to fieldwork in the form of semi-structured interviews.