The Brazilian model of corporate governance is characterized by a highly concentrated ownership structure, which usually culminates in an overlap between ownership and management. According to the literature, the accumulation of shares by the controller(s) can affect corporate performance due to both the alignment (or incentive) effect and the entrenchment effect. At first, the presence of large shareholders is associated with benefits for an organization because it increases the effectiveness of management monitoring. However, very high levels of ownership concentration can allow controllers to dominate the corporation's decision-making process, which could result in the expropriation of wealth from minority shareholders. The relevance of the ownership structure as an internal mechanism of corporate governance motivates the present study. This article aims to test whether ownership and control concentration influences corporate market value. An unbalanced panel was used for the period from 2001 to 2010, composed of 237 Brazilian non-financial publicly traded companies, totaling 1,199 observations. Dynamic regression models were used, estimated by the System Generalized Method of Moments (Sys-GMM), to mitigate possible sources of endogeneity, such as the omission of variables, the feedback effect, and the simultaneity. A quadratic relationship was found between cash flow rights of the largest shareholder and firm market value. Moreover, the results indicate that the corrected market value of the total shares held by the largest shareholder captured the incentive effect, while voting rights concentration captured the entrenchment effect.