The estimation of credit loss distribution of Iran’s banking industry using stress test

Document Type : Research Paper

Authors

1 Associate Professor, University of Allameh Tabatabai, Department of Economics, Tehran

2 allame tabatabai university

Abstract

In this paper, we estimate losses due to credit risk using stress test and calculate the minimum capital requirements under distressed and baseline scenarios. We use quarterly data from 2003:Q1 to 2016:Q2 (50 observations) for Iran’s banking industry and the economy. In the first step, the default probabilities are estimated using a series of macroeconomic variables.  Then, the default probabilities are simulated for one year time horizon using Monte-Carlo method. And finally, by using Loss Given Default (LGD) values and Exposed at Default (EAD) amounts, portfolio loss distribution is calculated. For this purpose, a hypothetical portfolio will be build. EAD for each loans is drawn randomly and uniformly distributed and LGD is given a fixed value.
To estimate default probability equation, in addition to the Wilson’s linear model, Quantile regressions are used. The results show that the loss distributions for all scenarios are skewed to the right. The amount of loss in the 50th quantile regression is closed to the Wilson model, but the loss in the 10th and 90th quantile regressions are different. In fact, the Wilson’s model overestimate the loss of 10% qunatile regression and underestimate the loss of 90% qunatile regression.
JEL ClassificationE17, G32, C21, E44, G21
 

Keywords

Main Subjects


امیری، فاطمه (1386). آزمون استرس ریسک نرخ بهره با استفاده از روش دیرش در یکی از بانک‌های خصوصی، دانشگاه صنعتی شریف، کارشناسی ارشد.
بامنی مقدم، محمد و خوش گویان فرد، علیرضا، (1383). کاربرد رگرسیون چندک در شناسایی شکل توزیع رفاه مورد انتظار جوانان، فصلنامه‌ی علمی پژوهشی رفاه اجتماعی، سال چهارم، شماره 15، صفحات 43-56.
حیدری،هادی، زواریان، زهرا و نوربخش، ایمان (1388). بررسی اثر شاخص‌های کلان اقتصادی بر مطالبات معوق بانک‌ها، فصلنامه‌ی پول و اقتصاد، شماره 4.
حیدری، هادی، صابریان رنجبر، سوده و نیلی، فرهاد (1391). تأثیر متغیرهای کلان اقتصادی بر ترازنامه‌ی بانک‌ها با رویکرد آزمون تنش (مطالعه‌ی موردی یکی از بانک‌های خصوصی)، فصلنامه‌ی پول و اقتصاد، شماره 8.
قالیباف اصل، حسن و افشار، منیژه (1392). بررسی کاربرد استفاده از مدل KMV در پیش­بینی ریسک ورشکستگی شرکت‌های پذیرفته شده در بورس اورق بهادار تهران و مقایسه مدل با نتایج مدل رتبه‌ی Z آلتمن، مجله‌ی مهندسی مالی و مدیریت اوراق بهادار، شماره‌ی بیست ویکم، زمستان 1393.
همتی، عبدالناصر و محبی­نژاد، شادی (1388)، ارزیابی تأثیر متغیرهای کلان اقتصادی بر ریسک اعتباری بانک‌ها، پژوهشنامه‌‌ی اقتصادی، ویژه‌ی نامه بانک، شماره ششم.
Allen, D. E., Boffey, R. R., & Powell, R. (2011). A Quantile Monte Carlo approach to measuring extreme credit risk”, Working Paper Series, Edith Cowan University.
Allen, D. E., Kramadibrata, AR., Powell, RJ., & Singh, AK. )2010(. "Using quantile regression to estimate capital buffer requirements for Japanese banks", Proceedings of the Globalization, Monetary Integration and Exchange Rate Regimes in East Asia Conference, Perth.
Bharath, S., & Shumway, T. (2008). “Forecasting Default with the KMV-Merton Model”, University of Mochigan.
Boss, M. (2002). “A Macroeconomic credit risk model for stress testing the Austrian credit portfolio”, Financial Stability Report 4, Oesterreichische Nationalbank.
Basel Committee on Banking Supervision (2006). International Convergence of Capital Measurement and Capital Standards: A Revised Framework Comprehensive Version.
CGFS (2000). “Stress testing by large financial institutions: current practice and aggregation issues”, Bank for International Settlements
CGFS (2005). “Stress testing at major financial institutions: survey result and practice”, Bank for International Settlement
Chan-Lau, J. A. (2013). “Market-Based Structural Top-Down Stress Tests of the Banking System”, International Monetary Fund, WP/13/88.
Chan-Lau, J. A. (2006). “Fundamentals-Based Estimation of Default Probabilities: A Survey. ” IMF Working Paper No. 06/149.
Covas, F., Rump, B., & Egon Z. (2014). “Stress-testing US bank holding companies: A dynamic panel quantile regression approach.” International Journal of Forecasting 30(3), 691-713.
Crouhy, M., Galai, D., & Mark, R. (2000). “Risk management”, Mc-Graw Hill.
Dimitris, N. (2002). “Stress Testing risk management strategies for extreme events”, Euromoney Books.
Drehman, M. (2005). “A market based macro stress test for the corporate credit exposure of UK banks”, London:bank of England, available via the internet:http://www. bis. org/bcbs/events/rtfo5 Drehamann. pdf.
Drehmann, M., Patton, A. J., & Sorensen, S. (2009). “Non-Linearities and Stress Testing,” in Proceedings of the Fourth Joint Central Bank Research Conference on Risk Measurement and Systemic Risk, Frankfurt, Germany, European Central Bank, pp. 213–301.
Drehmann, M. (2007). “Macroeconomic Stress-testing Banks: a Survey of Methodologies” in Stress-testing the Banking System, edited by Mario Quagliariello, 39-29. London: Cambridge University Press.
Foglia, A. (2009). “Stress Testing Credit Risk: A survey of Authorities Approaches”, Internarional Journal of Central Banking,  5(3).
Vazquez, F., Tabak, B., M., & Souto, M. (2012). “A Macro Stress Test Model of Credit Risk for the Brazilian Banking Sector, Journal of Financial Stability, 8(2), 69– 83.
Jordà, O. (2005). “Estimation and inference of impulse responses by local projections”, American Economic Review, 75 (1), 121-112.
Koenker, R. (2004). “Quantile Regression for Longitudinal Data,” Journal of Multivariate Analysis, 91(1), 74–89.
Koenker, R., & Xiao, Z. (2002). “Inference on the Quantile Regression Process”, Econometrica 70 (4), 1583-1612.
Merton, R. C. (1974). “On the Pricing of Corporate Debt: the Risk Structure of Interest Rates”, Journal of Finance, 29, 449–70.
Merton, Robert C. (1974). “On the Pricing of Corporate Debt: the Risk Structure of Interest Rates,” Journal of Finance,  29(2), 449–70.
Pesaran, M. H., Schuerman, T., Treutler, B. J., & Weiner, S. M. (2002). “Macroeconomic Dynamics and Credit Risk: a Global Perspective”, Journal of Money Credit and Banking, 31 (5).
Quagliariello, M. (2009). “stress-Testing The Banking System: Methodologies and Applications”, Cambridge university Press.
Ricardo, S., & Wanger, P. (2011). “Macro Stress testing of credit Risk Focused on the Tails”, Working Paper Series, Banko central Do Brasil.
Ruben, G. C., & Manuel, M. (2014). “Estimating the distribution of total default losses on the Spanish financial system”.
Simons, D., & Rolwes, F. (2009). “Macroeconomics Default Modeling and Stress Testing”, International Journal of Central Banking.
Virolainen, K. (2004). “Macro Stress Testing with a Macroeconomic Credit Risk Model for Finland”, Bank of Finland Discussion Papers, 11.
Wei, L., & Yang, Z. (2012). “Stress testing of Commercial banks’ Exposure to Credit Risk: A study based on write-off Nonperforming loans”, Asian social acience, 8(10).
Wilson, T. C. (1779a). “Portfolio Credit Risk (I)”, Risk.
Wilson, T. C. (1779b). “Portfolio Credit Risk (II)”, Risk.
Wong, J., Choi, K., & Fong, T. (2008). “A Framework for Stress Testing Bank’s Credit Risk,” The Journal of Risk Model Validation 2(1), 3–23.