Submitted by Diego Martins Silva (diego3martins@gmail.com) on 2015-04-22T19:03:54Z No. of bitstreams: 1 Dissertacao_final.pdf: 597953 bytes, checksum: 1bcdbee77f3bef20b251a0774042ebbf (MD5) / Approved for entry into archive by BRUNA BARROS (bruna.barros@fgv.br) on 2015-04-27T13:02:20Z (GMT) No. of bitstreams: 1 Dissertacao_final.pdf: 597953 bytes, checksum: 1bcdbee77f3bef20b251a0774042ebbf (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2015-05-04T12:52:18Z (GMT) No. of bitstreams: 1 Dissertacao_final.pdf: 597953 bytes, checksum: 1bcdbee77f3bef20b251a0774042ebbf (MD5) / Made available in DSpace on 2015-05-04T12:52:33Z (GMT). No. of bitstreams: 1 Dissertacao_final.pdf: 597953 bytes, checksum: 1bcdbee77f3bef20b251a0774042ebbf (MD5) Previous issue date: 2015-03-12 / In this work, we analyze network formation with wary agents. The model consists of two regions with (n/2) banks in each, where the connection between them occurs through interbank deposits. A bank run is possible to occur in each bank, due to an increase not expected of impatient agents, or due to contagion from run in another bank. If all banks form a high number of interconnections, they can eliminate possibility of contagion. If one does not prevent a contagion, it imposes all the others banks a positive possibility in the worst case. There are two well-defined regions of symmetric nash equilibrium with stable network, one in which all banks prevents the contagion in the worst case and the other in which no bank prevents. As a result of the coordination problem, equilibrium with contagion in the worst case can occur even pareto dominated by the equilibrium without contagion. Under certain conditions, contagion in the worst case occurs with a network pareto efficient, nevertheless the network is not the most resilient one. / Neste trabalho investigamos a formação de network considerando agentes cautelosos. O modelo consiste em duas regiões com (n/2) bancos em cada, onde a interligação entre eles ocorre através e depósitos interbancários. Cada banco está sujeito a corrida bancária, ou devido a um choque negativo de agentes impacientes, ou devido a contaminação da corrida de um banco pertencente a infraestrutura bancária. Os bancos podem tentar eliminar a possibilidade de contágio ao fazer um número alto de inter-ligações. Para isso, é necessário uma coordenação entre todos os bancos. Se um banco não se prevenir de um contágio, ele impõe a todos os outros a possibilidade de contágio no pior cenário. Há duas regiões bem definidas de equilíbrio de nash simétrico com network estável, uma na qual todos os bancos se previnem do cenário de contágio no pior cenário e a outra na qual nenhum banco se previne. Devido ao problema de coordenação, o equilíbrio com contágio no pior cenário pode ocorrer mesmo sendo pareto dominado pelo equilíbrio sem contágio. Sob certas condições, o equilíbrio com contágio ocorre com um network pareto eficiente. Neste caso o network eficiente é diferente do network mais resiliente ao contágio.

本研究旨在說明資本適足率對於銀行業資訊傳遞效果之影響，利用Allen and Gale (2000)模型討論在不完整市場結構下，銀行間因為持有銀行同業存款而形成相連的傳染途徑，進而影響整個系統，本研究擴展Allen and Gale (2000)的模型，加入資本適足率的考量，從而進一步探討透過資本適足要求能否有效提高銀行整體穩定性。 模型假設因為不同區域對於早、晚期消費需求不同，可藉由區域間的資源移轉，來達到最適分配情況。隨著資本適足率的納入，將改變最適分配解，同時分析緩衝(buffer)、擴散效果(spillover effect)及傳染(contagion)的變化。文中傳染定義為擴散效果扣除緩衝力道的淨結果，並說明若有超額流動性消費需求衝擊時，一家銀行的倒閉將如何傳染至整個銀行體系。 此研究發現，在資本適足規定下，若長期資產報酬率越大，會更有機會取得較大的緩衝能力，但將面對較大的擴散效果。關於傳染現象，則是發覺當銀行同業存款越小，在資本適足規定下的傳染機會越低；若長期資產的早期報酬率越大，同樣可降低發生傳染現象機率，即驗證資本適足率對於銀行穩定性的貢獻。 / The objective of this study is to testify the effect of capital requirement with regard to information transmission among banks. We develop a model based on Allen and Gale (2000) to discuss that under incomplete market structure, contagion channel is built because of interbank deposits market. We also expand Allen and Gale’s model by putting new parameter, capital requirement, into this model to analyze the impact of capital requirement with respect to stability in banking system. Due to different liquidity demands at each date in different regions, banks can exchange resources in the system to reach the first-best allocation. With capital requirement, the first-best allocation varies and so does buffer, spillover effect and contagion. In this article, contagion is defined as the net result of spillover effect minus buffer. Besides, we explain how the bankruptcy in one region evolves into the bankruptcy in the whole system under excess demand for liquidity. We find out that with capital requirement, if return of long-term asset at final date is higher, there will be more chances to have more buffers but larger spillover effect. As for contagion, it shows that with lower interbank deposits or higher return of long-term asset at early date, the possibility of contagion will be reduced. As a result, we can conclude that capital requirement really improves the stability in banking system.