This paper develops a rent-protection theory of corporate ownership structure – and in particular, of the choice between concentrated and dispersed ownership of corporate shares and votes. The paper analyzes the decision of a company’s initial owner whether to maintain a lock on control when the company goes public. This decision is shown to be very much influenced by the size that private benefits of control are expected to have. Most importantly, when private benefits of control are large – and when control is thus valuable enough – leaving control up for grabs would attract attempts by rivals to grab control and thereby capture these private benefits; in such circumstances, to preclude a control grab, the initia