Capital shocks, bank asset allocation, and the revised Basel Accord

In contrast to the 1988 Basel Accord (Basel I), the revised risk-based capital standards (Basel II) propose regulatory capital requirements based on credit ratings. This paper develops a theoretical model to analyze how banks will adjust their low and high credit risk commercial loans under the proposed newer standard. Capital-constrained banks respond to an adverse capital shock by reducing high credit risk loans, while under certain circumstances, low credit risk loans may actually increase. When compared to Basel I, it is shown that high-risk loans are reduced more under Basel II, but whether a bank reduces total lending more under Basel I or under the revised standards depends on a complex interaction of factors.     

Ratings based capital adequacy for securitizations

This paper develops a framework to measure the exposure to systematic risk for pools of asset securitizations and measures empirically whether current ratings-based rules for regulatory capital of securitizations under Basel II and Basel III reflect this exposure. The analysis is based on a comprehensive US dataset on asset securitizations for the time period between 2000 and 2008. We find that the shortfall of regulatory capital during the Global Financial Crisis is strongly related to ratings. In particular, we empirically show that insufficient capital is allocated to tranches with the highest rating. These tranches account for the greatest part of the total issuance volumes. Furthermore, this paper is the first to calibrate risk weights which account for systematic risk and provide sufficient capital buffers to cover the exposure during similar economic downturns. These policy-relevant findings suggest a re-calibration of RBA risk weights and may contribute to the current efforts by the Basel Committee on Banking Supervision and others to re-establish sustainable securitization markets and to improve the stability of the financial system.     

Basel II vs. Prompt Corrective Action: Which Is Best for Public Policy?

This paper evaluates Basel II as a tool for achieving public policy objectives relative to structured early intervention and resolution (SEIR) and prompt corrective action (PCA) in the U.S. It concludes that Basel II compares poorly in terms of maintaining a safe and sound banking system. Rather, Basel II resembles a "best practices" guide for banks in managing their credit risk. However, it may do damage through encouraging some large banks in the U.S. to successfully pressure their regulators to lower the capital trigger ratio for "adequately‐capitalized" status in order to benefit from any lower regulatory capital requirement that Basel II may give them.     

次贷危机对新资本协议实施的影响

本文以风险管理为切入点,讨论次贷危机与新资本协议之间的关系,试图回答业界对新资本协议制度合理性的某些质疑。与1988年资本协议相比,新资本协议建立了更具灵活性、适应性和前瞻性的资本监管制度,赋予资本充足率更加丰富的风险管理内涵,为商业银行改进风险管理提供了正向激励;次贷危机不仅未否认新资本协议的合理性,反而进一步凸现了全面实施新资本协议的重要性;新资本协议应顺应金融创新的趋势,吸取次贷危机的教训,做出适应性调整;虽然实施新资本协议不可能阻止金融危机再度发生,但可以提升银行体系应对外部冲击的能力,至少可以缓解未来金融危机的破坏力,从而提高社会福利。     

A Critique of Revised Basel II

This paper critiques the revised Basel II capital requirements for banks. To provide a framework for analysis, the XYZ theory of regulatory capital is formulated. Independent of the XYZ theory, we argue that the revised Basel II capital rule for credit risk is not a good approximation to the ideal rule. Based on this, and using the XYZ theory, we argue that: (1) the revised Basel II rules should not replace the existing approaches for determining minimal capital standards, but should be used in conjunction with them, and (2) that calibrating the capital rules to maintain aggregate market capital is a prudent procedure.     

Financial stability and Basel II

The Basel II Advanced Internal Ratings (AIRB) approach is compared to capital requirements set using an equilibrium structural credit risk model. Analysis shows the AIRB approach undercapitalizes credit risk relative to regulatory targets and allows wide variation in capital requirements for a given exposure owing to ambiguity in the definitions of loss given default and exposure at default. In contrast, the Foundation Internal Ratings Based (FIRB) approach may over-capitalize credit risk relative to supervisory objectives. It is unclear how Basel II will buttress financial sector stability as it specifies the weakest regulatory capital standard for large complex AIRB banks.      

Capital requirements under the credit risk-based framework

This work aims to study the hypothesis of lower capitalization of banks under the risk-based rules introduced in Basel II. In this sense, an assessment of the impact of these rules on the capital requirements for non-financial firms’ credit risk is performed. A comparison with Basel I is presented and intervals of variation for the risk drivers such that capital requirements exceed the ones under Basel I are established. Data for a European country supports the hypothesis of a smaller capitalization of banks under the risk-based framework, as far as credit risk in concerned.     

An Assessment of Basel II Procyclicality in Mortgage Portfolios

In this paper we develop a probability of default (PD) model for mortgage loans, taking advantage of the Spanish Credit Register, a comprehensive database on loan characteristics and credit quality. From that model, we calculate different types of PDs: point in time, PIT, through the cycle, TTC, average across the cycle and acyclical. Then, we compare capital requirements coming from the different Basel II approaches. We show that minimum regulatory capital under Basel II can be very sensitive to the risk measurement methodology employed. Thus, the procyclicality of regulatory capital requirements under Basel II is an open question, depending on the way internal rating systems are implemented and their output is utilised. We focus on the mortgage portfolio since it is one of the most under researched areas regarding the impact of Basel II and because it is one of the most important of banks’ portfolios.     

Procyclicality: The Macroeconomic Impact of Risk-Based Capital Requirements

Recent research on the Basel II capital framework suggests that binding capital requirements may be responsible for bank behaviour which causes procyclical amplifications of the macroeconomic cycle. This paper presents a model of the interrelations between the state of the economy, credit risk, and loan supply to clarify and quantify this effect. Special attention is paid to the fact that both regulatory and economic capital requirements can significantly influence loan supply, provided that they are binding. The model shows that both economic capital, based on a one-factor model, and the regulatory IRB requirements cause more procyclicality than the constant regulatory requirements of the Basel I capital accord. However, the overall impact depends on the interrelation of the regulatory requirements with economic capital. Based on this result, the replacement of the Basel I requirements with risk-sensitive IRB capital requirements boosts procyclicality under most, but not under all conditions.     

A cost-benefit analysis of capital requirements adjusted for model risk

Capital adequacy is the key microprudential and macroprudential tool of banking regulation. Financial models of capital adequacy are subject to errors, which may prevent from estimating a sufficient capital base to absorb bank losses during economic downturns. In this paper, we propose a general method to account for model risk in capital requirements calculus related to market risk. We then evaluate and compare our capital requirements values with those obtained under Basel 2.5 and the new Basel 4 regulation. Capital requirements adjusted for model risk perform well in containing losses generates in normal and stressed times. In addition, they are as conservative as Basel 4 capital requirements, but they exhibit less fluctuations over time.     

Capital adequacy rules, catastrophic firm failure, and systemic risk

This paper studies capital adequacy rules based on Value-at-Risk (VaR), leverage ratios, and stress testing. VaR is the basis of Basel II, and all three approaches are proposed in Basel III. This paper makes three contributions to the literature. First, we prove that these three rules provide an incentive to increase the probability of catastrophic financial institution failure. Collectively, these rules provide an incentive to increase (not decrease) systemic risk. Second, we argue that an unintended consequence of the Basel II VaR capital adequacy rules was the 2007 credit crisis. Third, we argue that to reduce systemic risk, a new capital adequacy rule is needed. One that is based on a risk measure related to the conditional expected loss given insolvency.     

《银行资本充足率监管征求意见稿》的影响研究

2011年5月,银监会下发了融合《巴塞尔协议II》及《巴塞尔协议III》内关于资本计量、管理等内容的《银行资本充足率监管征求意见稿》,这标志着金融危机后我国的新监管标准即将落地。该监管新规将使国有五大行资本充足率下降。五大行可以从补充资本、降低加权风险资产、增强资本管理能力等方面应对监管新规。     

Loan pricing under Basel capital requirements

We analyze the loan pricing implications of the reform of bank capital regulation known as Basel II. We consider a perfectly competitive market for business loans where, as in the model underlying the internal ratings based (IRB) approach of Basel II, a single risk factor explains the correlation in defaults across firms. Our loan pricing equation implies that low risk firms will achieve reductions in their loan rates by borrowing from banks adopting the IRB approach, while high risk firms will avoid increases in their loan rates by borrowing from banks that adopt the less risk-sensitive standardized approach of Basel II. We also show that only a very high social cost of bank failure might justify the proposed IRB capital charges, partly because the net interest income from performing loans is not counted as a buffer against credit losses. A net interest income correction for IRB capital requirements is proposed.     

Integrated models of capital adequacy – Why banks are undercapitalised

With the majority of large UK and many US banks collapsing or being forced to raise capital over the 2007–9 period, blaming bankers may be satisfying but is patently insufficient; Basel II and Federal oversight frameworks also deserve criticism. We propose that the current methodological void at the heart of Basel II, Pillar 2 is filled with the recommendation that banks develop fully-integrated models for economic capital that relate asset values to fundamental drivers of risk in the economy to capture systematic effects and inter-asset dependencies in a way that crude correlation assumptions do not. We implement a fully-integrated risk analysis based on the balance sheet of a composite European bank using an economic-scenario generation model calibrated to conditions at the end of 2007. Our results suggest that the more modular, correlation-based approaches to economic capital that currently dominate practice could have led to an undercapitalisation of banks, a result that is clearly of interest given subsequent events. The introduction of integrated economic-scenario-based models in future can improve capital adequacy, enhance Pillar 2’s application and rejuvenate the relevance of the Basel regulatory framework.     

Basel II: Correlation Related Issues

Basel II aims to aggressively improve on Basel I, and is projected to capitalize on the technological advancements that have permeated the financial industry since Basel I. This paper examines the correlation issues that arise, and provides recommendations on implementation as we move forward. We provide the following results: (1) We demonstrate that fixing asset value correlations by regulators without a specification of business unit granularity and aggregation impacts franchise risk. (2) Loss distributions for credit risk are more sensitive to correlation assumptions that those for market risk; arbitrary, inaccurate correlation specifications can cause large errors in capital requirements. (3) Current regulations do not recognize that credit losses depend on four distinct correlations, not just one. (4) Recovery rates may be determined uniformly across banks. (5) Tail risk comes from LGD correlations and non-Gaussian risks. (6) The 1-year VaR horizon causes distortions especially when regimes and pro-cyclicality are involved. (7) We recommend a quantitative measure for implementing market discipline, the third pillar of the Basel II accord. Therefore, this paper highlights many issues that may be addressed using the tools banks already employ for internal risk management.     

Risk-based capital requirements for mortgage loans

We contribute to the debate over the reform of the Basel Accord by developing risk-based capital requirements for mortgage loans held in portfolio by financial intermediaries. Our approach employs simulation of both economic variables that affect default incidence and conditional loss probability distributions. Results indicate that appropriate capital charges for credit risk vary substantially with loan characteristics and portfolio geographic diversification. Hence, rules that offer little risk differentiation, including the current Basel I regime and “standardized” approach proposed in Basel II result in significant divergence between regulatory and economic capital. These results highlight the incentive problems inherent in simplified methods of capital regulation.     

On the necessity of five risk measures

The banking systems that deal with risk management depend on underlying risk measures. Following the Basel II accord, there are two separate methods by which banks may determine their capital requirement. The Value at Risk measure plays an important role in computing the capital for both approaches. In this paper we analyze the errors produced by using this measure. We discuss other measures, demonstrating their strengths and shortcomings. We give examples, showing the need for the information from multiple risk measures in order to determine a bank’s loss distribution. We conclude by suggesting a regulatory requirement of multiple risk measures being reported by banks, giving specific recommendations.     

How to make regulators and shareholders happy under Basel III

In addition to the Basel II capital ratio, Basel III requires banks to respect additional ratios, such as leverage ratio, liquidity coverage ratio and net stable funding ratio. Banks are required to be compliant with all four constraints simultaneously. Our article provides a framework for banks to help their search for an optimal transition from Basel II to Basel III. Recognizing that banks’ return and the four constraints are of linear type, this search can be formulated as a linear program and solved by standard software. Incorporating uncertainty on future defaults, risk weights and withdrawals and formulating the problem as a Chance constrained model does not only yield optimal transition strategies but also determines the internal thresholds for the Basel III-ratios. Our approach needs two standard inputs from controlling: profit margins per product and non-financial adjustment costs to expand or cut back business. The adjustment cost can be used to calibrate the model to the current business mix. This calibration can be done by bank outsiders and allows the model to be used in impact studies to replace ad hoc strategies. To highlight its practicality, we apply our model to a typical German bank with a business mix that complies with Basel II, but not with the Basel III-, capital-, leverage- and net stable funding-ratio. Assuming that its business model is optimal under Basel II, we find that this bank would achieve compliance restructuring its funding side by replacing interbank funding by capital and retail deposits. Additional uncertainty would amplify the magnitude of the changes, but would still affect the same positions. These findings are robust against alternative margin definitions and adjustment cost levels.     

Should the insurance industry be banking on risk escalation for solvency II?

Basel II introduced a three pillar approach which concentrated upon new capital ratios (Pillar I), new supervisory procedures (Pillar II) and demanded better overall disclosure to ensure effective market discipline and transparency. Importantly, it introduced operational risk as a standalone area of the bank which for the first time was required to be measured, managed and capital allocated to calculated operational risks. Concurrently, Solvency II regulation in the insurance industry was also re-imagining regulations within the insurance industry and also developing operational risk measures. Given that Basel II was first published in 2004 and Solvency II was set to go live in January 2014. This paper analyses the strategic challenges of Basel II in the UK banking sector and then uses the results to inform a survey of a major UK insurance provider. We report that the effectiveness of Basel II was based around: the reliance upon people for effective decision making; the importance of good training for empowerment of staff; the importance of Board level engagement; and an individual's own world view and perceptions influenced the adoption of an organizational risk culture. We then take the findings to inform a survey utilizing structural equation modelling to analyze risk reporting and escalation in a large UK insurance company. The results indicate that attitude and uncertainty significantly affect individual's intention to escalate operational risk and that if not recognized by insurance companies and regulators will hinder the effectiveness of Solvency II implementation.     

Optimal portfolios with minimum capital requirements

We propose a novel approach to active risk management based on the recent Basel II regulations to obtain optimal portfolios with minimum capital requirements. In order to avoid regulatory penalties due to an excessive number of Value-at-Risk (VaR) violations, capital requirements are minimized subject to a given number of violations over the previous trading year. Capital requirements are based on the recent Basel II amendments to account for the ‘stressed’ VaR, that is, the downside risk of the portfolio under extreme adverse market conditions. An empirical application for two portfolios involving different types of assets and alternative stress scenarios demonstrates that the proposed approach delivers an improved balance between capital requirement levels and the number of VaR exceedances. Furthermore, the risk-adjusted performance of the proposed approach is superior to that of minimum-VaR and minimum-stressed VaR portfolios.