This research assesses the success of collaboration agreements through changes in competitive strength rather than the longevity of the transactions or the formality and visible structure of the agreements. To establish competitive strength, as development and renewal of capabilities, the research proceeds through the review of the alliance between the Co-operative Permanent Building Society, the Co-operative Wholesaling Society, Scottish Co-operative Wholesaling Society and Co-operative Insurance Society (1943-65). This co-operative agreement allows insights into the strategy of non-banks and non-finance participants aiming to enter British bank markets. The research also considers the rather different process at Spanish savings banks, with a particular focus on IT outsourcing (1977-95). Cases in the UK and Spain form an historical argument and are used to demonstrate how the implementation of strategy is as important as strategic visioning to achieve competitive advantage in bank markets.