Ever since Adam Smith there has been a contention that dispersed ownership in a joint stock company is accompanied by low firm performance. This belief has reached its theoretical hights in agency theory. The aim of the paper is to show that mthe contention has to be developed in order to be more attuned with empirical data. It will be argued 1.) That the influence of ownership structure upon performance is mediated through mechanisms inside the firm, the strategy being the most prominent; 2.) That performance has to be divided into profit and risk, and into firm performance, using accounting data, and market performance, using share market performance data; 3.) That the ownership structure is not exclusively a factor that influences the firm, but that the firm and its strategy influence the ownership structure through attracting certain shareholders and repulse others; 4.) That ownership structure is but one mechanism of several corporate governance mechanisms and that performance is ultimately influenced by the mix of the mechanisms; and 5.) Those institutional differences, such as culture, traditions, legislation and history, influence the opportunity set of corporate governance structures and therefore the relative importance of ownership structures in influencing the performance of the firm. A data set from Sweden and from the hard years of 1990 is used in order to empirically support the statements.