傳統研究股利政策的理論提議五種財務管理所必須考慮的不完美因素，分別是賦稅、資訊不對稱、不完全契約、機構限制及交易成本。本文和傳統研究股利政策不同之處在於從投資人之間的異質信念角度探討公司的最適股利政策。
本文的第一個模型係研究完全資訊無磨擦經濟體且有不同信念的投資人其投資/股利政策。當樂觀型投資人的財富受到限制時，經理人將股票同時賣給樂觀型投資人及至少賣給一個持有部分該股票的悲觀型投資人，並採用高股利政策 - 配發現金股利D=X0-ap+1。反之當樂觀型投資人的財富未受限制時，經理人將股票全部賣給樂觀型投資人並採用低股利政策 - 現金股利D=X0-ao+1。因此，即使在完全資訊時公司的投資/股利政策也將受到異質性投資人之間的不同信念而改變。
本文的第二個模型延續Miller and Rock(1985)理論，研究資訊不對稱下具有不同信念的異質性投資人，在兩期模型之下公司的最適股利政策。研究結果顯示，悲觀/樂觀投資人的比例及其異質信念的比例均會影響公司的最適股利政策。當悲觀/樂觀投資人之比例增加時，經理人應採取高股利政策。另一方面，當樂觀及悲觀投資人信念同時增加時，例如新的生物科技產業開發，此時應採取低股利政策。
依據前述分析結果顯示，公司的最適股利政策會受到異質性投資人之間的不同信念而改變。公司的最適股利政策有別於MM股利無關論，並非因為賦稅、資訊不對稱、不完全契約、機構限制及交易成本之原因，而是因為異質性投資人之間的不同信念所構成。

The typical theoretical work on dividend policy suggests five possible imperfections that management should consider. They are taxes, asymmetric information, an incomplete contract, institutional constraints and transaction costs. Different from the typical framework, this dissertation is to study the optimal dividend poly with heterogeneous beliefs among investors.
The first model in this study has analyzed investment/dividend policy with heterogeneous beliefs-the full information model in a frictionless economy with divergent types of shareholders. A high dividend policy is optimal with limited endowment for the optimistic investors as the stocks are sold not only to type-o investors, but also to at least one type-p investor holding some shares. A low dividend policy is appropriate with cash dividend D= X0-ao+1 is optimal as the shares are sold only to the type-o investors. Heterogeneous beliefs of investors change dividend policy given the same information even under full information.
Following the Miller and Rock (1985) theory, the second model in this dissertation has analyzed heterogeneous beliefs among investors-the two period model in leading to changing a firm’s optimal dividend policy. A firm’s optimal dividend policy is changed not only by the ratio of the pessimistic to optimistic investors, but also heterogeneous beliefs. An increase in the ratio of pessimistic to optimistic investors will result in a higher dividend. On the other hand, as the beliefs of both optimistic and pessimistic investors increase, i.e. a new biotechnology is innovated, a relative low dividend policy is appropriate.
Based on the previous analysis, the results show that optimal dividend policy with heterogeneous beliefs among investors in a firm’s earnings exists under heterogeneous beliefs framework. A firm’s optimal dividend policy is different from that of the MM dividend invariance theorem. It is not because of taxes, asymmetric information, incomplete contracts, institutional constraints and traction costs, but heterogeneous beliefs of investors.

Chap. 1 Introduction 1
1.1 Motivation 1
1.2 Research objectives 4
1.3 Dissertation framework 5
Chap. 2 Literature review 7
2.1 Dividend policy 7
2.2 Heterogeneous beliefs 11
2.3 Dividend policy with heterogeneous beliefs among the investors 13
Chap. 3 Investment/dividend policy with heterogeneous beliefs-the full information model 16
3.1 Homogeneous beliefs among the investors 17
3.1.1 Homogeneous beliefs 17
3.1.2 Homogeneous beliefs in the production/investment function 17
3.2 Heterogeneous beliefs among the investors 19
3.2.1 Heterogeneous beliefs 19
3.2.2 Heterogeneous beliefs on Production/investment function 20
3.3 Description of the model 22
3.3.1 The entrepreneur’s decision problem 22
3.3.2 With unlimited wealth for the optimistic investors 23
3.3.3 With limited wealth for the optimistic investors 26
Chap. 4 Dividend policy with heterogeneous beliefs-the asymmetric information model 29
4.1 The Miller and Rock model 30
4.2 Description of the model 32
4.3 The Entrepreneur’s Decision Problem 34
4.3.1 Homogeneous beliefs in the production/investment function 34
4.3.2 Heterogeneous beliefs on earning 35
4.4 Comparative static analysis 45
Chapter 5 Conclusions and suggestions 54
5.1 Conclusions 54
5.2 Further study 56
References 57
Appendix：Symbols list 60

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