This paper contributes to the literature of ownership, control and performance by exploring these relationships for Swedish listed companies (1997-2002). A marginal q will be used as measures of economic performance. Marginal q was presented in an article by Mueller and Reardon in 1993 and has recently been used in empirical studies of ownership and performance by among others Gugler and Yurtoglu (2003). Frequently an average Tobin’s q is used in studies of this type, but Tobin’s q has a number of disadvantages which can be circumvented by employing a marginal q. In addition to marginal q estimations have been made with the valuation ratio as performance measure. The valuation ratio is interesting from a theoretical viewpoint, as it is an efficiency measure that plays a central role in Marris (1964) growth model of the firm. It is also easy to compute and is related to Tobin´s q. This study adds to earlier studies by using Swedish data with its specificities in form of pyramid ownership and a vote differential. The relationships between the two performance measures and different ownership characteristics like ownership concentration and foreign ownership is investigated. We find that firms, on average, are making inferior investment decisions and that the Swedish corporate governance system have some efficiency drawbacks.