This paper investigates into the role of dividend in controlling agnecy between large and small shareholders and getween managers and sahreholders. Data includes 1,341 samples of listed firma in the Stock Exchange of Thailand during 2002 to 200/8. Thailand has high concentration of ownership and there may be two groups of firms. One with agency conflict between large controlling shareholder and other shateholders and one between managers and shareholders. The empirical findings suggest there are two groups of firm. Results provide evidence of rent extraction by controlling shareholder. The second largest and other shareholder are not effective in moitoring the largest. Among firms with no controlling shareholder, the largest shareholder has been effective in monitoring the management. Share concentration by the second largest does not help improve the effictiveness of monitoring. Monitoring is both statistically and economically significant.
