This dissertation consists of three essays in corporate governance. The first essay, titled ¡§Control or Invest: Complex Interests of Managerial Stockholdings¡¨ examines the structural relation between managerial ownership and firm performance. By using simultaneous equation models and considering the complex interests of management, our results show that complicated mutual effects exist between managerial ownership and firm performance. In diffused ownership structure (0-13%), better firm performance may induce management to hold more stockholding, indicating possible investment purpose that is not addressed in previous studies. Management with mid-range of stockholdings (13%-50%), have positive effect on firm performance but not vice versa, which agrees with the ¡§convergence-of-interest hypothesis¡¨. For highly concentrated ownership structure (>50%), negative mutual effect exists, which agrees with the ¡§entrenchment hypothesis¡¨, giving notice to protect minority shareholders. The second essay, titled ¡§The Discrepancy of R&D Expenditure, Ownership Structure and Performance between Electronic and Non-electronic Industries¡¨ addresses on the mutual effects among R&D expenditure, ownership structure and firm performance in electronic industry. The characteristics of high research expenditure, high performance, and stock-based compensation plan of electronic industry may exaggerate the mutual effects between these three factors than companies in non-electronic industry. The empirical evidence first shows that better firm performance will result in higher managerial equity in both electronic and non-electronic industries. Another finding is that electronic industry has higher and more stable research expenditure, no matter firm¡¦s performance; while non-electronic industry spends more in research only when the firm is doing well. The third essay, ¡§The Adjustment and Determination of Ownership Change¡¨, is used to examine the equilibrium hypothesis regarding managerial ownership variation. The equilibrium hypothesis assumes that managers will continuously re-optimize their ownership to maximize firm¡¦s value. In this essay, instead of studying the cross-sectional relationship between managerial ownership and firm performance, we use a dynamic setting to examine how managers adjust their ownership over time and what factors will determine the within firm variation. It is shown that there is small within firm variation in managerial ownership with strong mean-reversion adjustment the entire sample. The results also show that firm characteristics like debt ratio, R&D expenditure and operating income do not relate significantly to within firm variation, but firm performance and institutional parameters like the reselection of board members, stock turnover and ownership level do. This thesis contributes to provide investment purpose as an alternative explanation for insiders¡¦ stockholding, in addition to the expropriation activities that is major concern in prior studies. The change analysis further provides more understanding of within firm variation vertically that is still vague in the literature (HHP, 1999). These new findings add knowledge to managerial ownership in emerging market like Taiwan. The managerial implication is that investors may not fully depend on manager¡¦s self-discipline to solve agency problem. Outside supervision, including independent board member and supervisor, institutional investors and corporate governance evaluation, could be emphasized to reinforce corporate governance.