信用市場發生資訊不對稱時，貸款申請人對自己的型態瞭若指掌，而銀行

卻因對貸款申請人資訊相對不足而必須承受倒帳的風險。銀行若欲保障利

潤而提高擔保品或利率，反而易引起道德危機與逆選擇的問題，造成銀行

利潤下降。多數文獻常以信用分配、自我選擇機能、信號機能來探討銀行

面臨資訊不對稱所發生的狀況，本文就是以信號賽局來探討資訊不對稱下

的銀行放款決策。在以信號機能分析銀行放款市場的文獻中，Milde &

Riley (1988)以貸款額為信號變數，分別用乘法與加法形式利潤函數探討

不對稱資訊下的銀行放款決策。薛舜仁(1993)則以擔保品為信號變數，運

用乘法形式利潤函數來探討。本文則延續薛舜仁的分析方法，在貸款額固

定下，利用貸款申請人型態、擔保品、計劃報酬隨機性形成利潤函數，惟

此利潤函數，呈現的是Milde & Riley 的加法形式利潤函數。透過貸款申

請人無異曲線斜率不同所隱含邊際替代率不同的特性，分析出不對稱資訊

下的均衡契約。由於本文結果與 Milde & Riley 及薛舜仁的結果不同，

所以我們將各結果列出比較，發現在資訊不對稱時，以債權安全目標設計

契約時，債信高的申請人會選擇高貸款額或低擔保品但放款利率高的契約

。當銀行為防止高風險者因擔保品負擔過重退出市場，而以風險角度設計

契約時，則均衡時，高債信者會選擇低貸款額或高擔保品，但放款利率低

的契約。

 姜堯民「不對稱資訊下銀行放款契約訂定之研究」，政大企研所碩士論文，民國79年6月
 俞海琴「資訊不對稱夏本國銀行放款市場之研究」政大企研所博士論文，民國81年1月
 賈毅然「信用配給之實證研究」台大商研所碩士論文，民國75年7月
 薛舜仁「資訊不對稱下銀行之放款策略－信號賽局理論之應用」政大國貿所碩士論文，民國82年6月

二、英文部份:
[1] Besanko, David and Anjan V. Thakor(1987) “Competitive Equilibrium in the Credit Market under Asymmetric Information, “ Journal of Economic Theory, 42, pp167-182
[2]Baster, Helmut(1985) “Screening vs. Rationing in Credit Markets sith Imperfect Information,” American Economic Review, 75, PP.850-855
[3]Bester, Helmut(1987) “The Role of Collateral in Credit Markets with Imperfect. Information,” European Economic Review,31, pp887-899.
[4]Chan, Yuk-Shee, and Thakor, Anjan V. (1987) “Collateral and Competitive Equilibria with Moral Hazard and Private Information,” Journal of Finance, 52,PP345-363
[5]Cho, In-Koo and Kreps, David M.(1987) “Signalling Games and Stable Equilibria,” The Quarterly Journal of Economics, 102, pp 179-221.
[6]Enger, M.P. and L.Fernandez (1987) “Market Equilitrium with Hiddern Knowledge and Self-Selection,” Econometrica, 55, pp425-440.
[7] Enger, M.P.(1987) "Signalling with l'vlany Signals,"
Econometerica,55, P P663- 674.
[8] Hillwig, Martin(1987) "Some Recent Developments in the Theory
of Compensation in rvlarkets with Adverse Selection" 8uropean
Economic Review)31,PP319-325.
[9] Fudenberg, Drew and Tirole, Jean(1991) Game Theory. The
MIT Press.
[10] Gibbons, Robert(1992) Game Theory f07' Applied Economists.
Princeton Unversity Press.
[11] Kreps, David M. and 'Nilson , Robert(1982) "Sequential EquiIi
bria," Econometria)50,PP863-894.

[12] Milde, Hellmuth and Riley,
John G.(1988) ('Signalling in Credit Markets," The Quarterly
Journal of Economics]Feb.,PP101-129.
[13] Milgrom Paul and Roberts John(1986) "Price and Advertising
Signals of Product Quality,ll Journal of Political
Economy] V94,PP796-821.
[14] Stiglitz, Joseph and iNeiss, Andrew(19S1) (' Credit Rationing
in Markets with Imperfect Information," American Economic
Review,71 ,PP393-410.
[15] Thomas E. Copeland and J. Fred W'eston Financial Theory
and Corporate Policy Addison- W-esley Publishing Company,
Third Edition
[16] yVette, Hildegard C.(1983) "Collateral in Credit Rationing in
Markets with Imperfect Information:Note:' The Amer£can Economic
Review,73,PP442-445.

[17] Wilson, C.A.(1977) "A Model of Insurance tvlarkets vvith Incomplete
Information" Journal of Economic Theory)16,PP167-207.
[18] Wilson, Robert(19S5) "l"Multi-Dimensional Signalling,•' Economics
Letters)9 ,PP17-21.