Concentration Risk in Credit Portfolios and Its Treatment Under Basel II

  • Martin Hibbeln
Part of the Contributions to Economics book series (CE)


Banks often only look at one side of concentration risk – the diversification effect. Thus, it is often argued that the requirements of Pillar 1 are the non-diversified benchmark and therefore an upper barrier for the true capital requirement. But as the Basel II formulas have been calibrated on well-diversified portfolios with low name and low sector concentrations, it is indeed possible that banks should have an additional capital buffer to capture concentration risk. Furthermore, some theoretical models as well as empirical studies have demonstrated that concentrated banks can be less risky than diversified banks, which is mainly due to better monitoring abilities of specialized financial institutions. However, even if it can be economically reasonable to be focused on particular industry sectors or geographical regions, the capital requirements should still be higher than for diversified banks. The main argument is that although a specialized bank could benefit from the ability to invest in firms with higher quality (of course it is not even clear that a higher risk-return premium is earned through lower risk), the bank would still be very vulnerable if the specific sector is in an economic downturn scenario. But exactly such a downturn scenario, often quantified with the VaR, plays the decisive role for the capital requirements.


Gini Coefficient Credit Default Swap Capital Requirement Lorenz Curve Collateralized Debt Obligation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. Acharya VV, Hasan I, Saunders A (2006) Should banks be diversified? Evidence from individual bank loan portfolios. J Bus 79(3):1355–1412CrossRefGoogle Scholar
  2. Bank M, Lawrenz J (2003) Why simple, when it can be difficult? Some remarks on the Basel IRB approach. Kredit Kapital 36(4):534–556Google Scholar
  3. Basel Committee on Banking Supervision (2004a) Background note on LGD quantification. Bank for International Settlements, BaselGoogle Scholar
  4. Basel Committee on Banking Supervision (2004b) Bank failures in mature economies. BCBS Working Paper No. 13. Bank for International Settlements, BaselGoogle Scholar
  5. Basel Committee on Banking Supervision (2005a) International convergence of capital measurement and capital standards – a revised framework, Updated November 2005, Bank for International Settlements, BaselGoogle Scholar
  6. Basel Committee on Banking Supervision (2005b) Workshop ‘Concentration risk in credit portfolios’: background information. Bank for International Settlements, Basel. Accessed 18 Aug 2009
  7. Basel Committee on Banking Supervision (2005c) Workshop ‘Concentration risk in credit portfolios’: selected literature on concentration risk in credit portfolios. Bank for International Settlements, Basel. Accessed 18 Aug 2009
  8. Basel Committee on Banking Supervision (2006) Studies on credit risk concentration: an overview of the issues and a synopsis of the results from the research task force project. BCBS Working Paper No. 15, Bank for International Settlements, BaselGoogle Scholar
  9. Behr A, Kamp A, Memmel C, Pfingsten A (2007) Diversification and the banks’ risk-return-characteristics – evidence from loan portfolios of German banks. Discussion Paper, Series 2: Banking and Financial Studies, Deutsche Bundesbank (5)Google Scholar
  10. Berger PG, Ofek E (1996) Bustup takeovers of value-destroying diversified firms. J Fin 51(4):1175–1200CrossRefGoogle Scholar
  11. Bluhm C, Overbeck L (2007) Structured credit portfolio analysis, baskets and CDOs. CRC, Boca Raton, FLGoogle Scholar
  12. Bluhm C, Overbeck L, Wagner C (2003) An introduction to credit risk modeling. CRC, LondonGoogle Scholar
  13. Cespedes J, de Juan Herrero J, Kreinin A, Rosen D (2006) A simple multi-factor “factor adjustment” for the treatment of diversification in credit capital rules. J Credit Risk 2(3):57–85Google Scholar
  14. Committee of European Banking Supervisors (2006). Technical aspects of the management of concentration risk under the supervisory review process. CEBS, LondonGoogle Scholar
  15. Davis M, Lo V (2001) Infectious defaults. Quant Fin 1(4):382–387CrossRefGoogle Scholar
  16. DeLong G (2001) Stockholder gains from focusing versus diversifying bank mergers. J Fin Econ 59(2):221–252CrossRefGoogle Scholar
  17. Demsetz RS, Strahan P (1997) Diversification, size, and risk at bank holding companies. J Money Credit Bank 29(3):300–313CrossRefGoogle Scholar
  18. Deng S, Elyasiani E, Mao C (2007) Diversification and the cost of debt of bank holding companies. J Bank Fin 31(8):2453–2473CrossRefGoogle Scholar
  19. Denis DJ, Denis DK, Sarin A (1997) Agency problems, equity ownership, and corporate diversification. J Fin 52(1):135–160CrossRefGoogle Scholar
  20. Deutsche Bundesbank (2006) Konzentrationsrisiken in Kreditportfolios. Monatsbericht 58(6):35–54Google Scholar
  21. Diamond D (1984) Financial intermediation and delegated monitoring. Rev Econ Stud 51(3):393–414CrossRefGoogle Scholar
  22. Düllmann K (2006). Measuring business sector concentration by an infection model. Discussion Paper, Series 2: Banking and financial studies. Deutsche Bundesbank (3)Google Scholar
  23. Düllmann K (2007) Measuring concentration risk in credit portfolios. In: Christodoulakis G, Satchell S (eds) The analytics of risk model validation. Academic Press, Amsterdam, pp 59–78Google Scholar
  24. Düllmann K, Masschelein N (2007) A tractable model to measure sector concentration risk in credit portfolios. J Fin Serv Res 32(1):55–79CrossRefGoogle Scholar
  25. Egloff D, Leippold M, Vanini P (2007) A simple model of credit contagion. J Bank Fin 31(8):2475–2492CrossRefGoogle Scholar
  26. Emmer S, Tasche D (2005) Calculating credit risk capital charges with the one-factor model. J Risk 7(2):85–103Google Scholar
  27. EU (2006) Directive 2006/48/EC of the European Parliament and of the Council of 14 June 2006 Relating to the taking up and pursuit of the business of credit institutions (Recast). Official Journal of the European UnionGoogle Scholar
  28. Giesecke K, Weber S (2006) Credit contagion and aggregate losses. J Econ Dyn Control 30(5):741–767CrossRefGoogle Scholar
  29. Gordy MB (2001) A risk-factor model foundation for rating-based capital rules. Working Paper. Board of Governors of the Federal Reserve System, Washington DCGoogle Scholar
  30. Gordy MB (2003) A risk-factor model foundation for rating-based capital rules. J Fin Intermediation 12(3):199–232CrossRefGoogle Scholar
  31. Gordy MB (2004) Granularity adjustment in portfolio credit risk measurement. In: Szegö G (ed) Risk measures for the 21st century. Wiley, New York, pp 109–121Google Scholar
  32. Gordy MB, Lütkebohmert E (2007) Granularity adjustment for Basel II. Discussion Paper, Series 2: Banking and financial studies, Deutsche Bundesbank (1)Google Scholar
  33. Gouriéroux C, Laurent J, Scaillet O (2000) Sensitivity analysis of values at risk. J Empir Fin 7(3–4):225–245CrossRefGoogle Scholar
  34. Gürtler M, Heithecker D, Hibbeln M (2008a) Concentration risk under Pillar 2: when are credit portfolios infinitely fine grained? Kredit Kapital 41(1):79–124CrossRefGoogle Scholar
  35. Gürtler M, Hibbeln M, Olboeter S (2008b) Design of collateralized debt obligations: the impact of target ratings on the first loss piece. In: Gregoriou GN, Ali P (eds) The credit derivatives handbook. McGraw-Hill, New York, pp 203–228Google Scholar
  36. Gürtler M, Hibbeln M, Vöhringer C (2010) Measuring concentration risk for regulatory purposes. J Risk 12(3):69–104Google Scholar
  37. Hammarlid O (2004) Aggregating sectors in the infectious defaults model. Quant Fin 4(1):64–69CrossRefGoogle Scholar
  38. Hansen M, Ramadurai K, Merritt R, Linnell I, Olert J, Jennings S (2009) Basel II’s proposed enhancements: focus on concentration risk. Credit Market Research, Fitch RatingsGoogle Scholar
  39. Joint Forum (2008) Cross-sectoral review of group-wide identification and management of risk concentrations. Bank for International Settlements, BaselGoogle Scholar
  40. Joint Forum (2009) Joint Forum History, Bank for International Settlements. Accessed 18 Aug 2009
  41. Kamp A, Pfingsten A, Porath D (2005) Do banks diversify loan portfolios? a tentative answer based on individual bank loan portfolios. Discussion Paper, Series 2: Banking and financial studies, Deutsche Bundesbank (3)Google Scholar
  42. Markowitz H (1952) Portfolio selection. J Fin 7(1):77–91Google Scholar
  43. Markowitz H (1959) Portfolio selection: efficient diversification of investments. Wiley, New YorkGoogle Scholar
  44. Martin R, Wilde T (2002) Unsystematic credit risk. Risk 15(11):123–128Google Scholar
  45. Neu P, Kühn R (2004) Credit risk enhancement in a network of interdependent firms. Physica A Stat Mech Appl 342(3–4):639–655CrossRefGoogle Scholar
  46. Pykhtin M (2004) Multi-factor adjustment. Risk 17(3):85–90Google Scholar
  47. Pykhtin M, Dev A (2002) Analytical approach to credit risk modelling. Risk 15(3):26–32Google Scholar
  48. Rau-Bredow H (2002) Credit portfolio modelling, marginal risk contributions, and granularity adjustment. Working Paper, WürzburgGoogle Scholar
  49. Rau-Bredow H (2005) Unsystematic credit risk and coherent risk measures. Working Paper, WürzburgGoogle Scholar
  50. Seidman L, Litan R, White L, Silverberg S (1997) Lessons of the eighties: what does the evidence show. Federal Deposit Insurance Corporation, http// Accessed 18 Aug 2009
  51. Servaes H (1996) The value of diversification during the conglomerate merger wave. J Fin 51(4):1201–1225CrossRefGoogle Scholar
  52. Tasche D (2006b) Measuring sectoral diversification in an asymptotic multi-factor framework. J Credit Risk 2(3):33–55Google Scholar
  53. Wilde T (2001) Probing granularity. Risk 14(8):103–106Google Scholar
  54. Wilde T (2003) Derivatives of VaR and CVaR. Working Paper, CSFBGoogle Scholar
  55. Winton A (1999) Don’t put all your eggs in one basket? diversification and specialization in lending. Working Paper,

Copyright information

© Physica-Verlag HD 2010

Authors and Affiliations

  1. 1.Institute of Finance Carl-Friedrich-Gauß-FacultyTechnische Universität BraunschweigBraunschweigGermany

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