How has ownership and control changed over the years according to Kay?

Kay argues that today control matters more than ownership. In the mid 19th century, ownership meant control. In the mid 1930s the ownership and control were split. Today, rarely the owner controls the means of production in large firms. However, there can be tension between manager’s objectives and shareholders’ (i.e., owners). This creates the need of managerial theories of the firm, as managers now hold the control of the firm.