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.     

A leverage ratio rule for capital adequacy

This paper studies the economic foundations for maximum leverage ratio capital adequacy rules. The paper makes three contributions to the literature. First, we show how to determine the maximum leverage ratio such that the probability of insolvency is less than some predetermined quantity. Two, we show that a leverage ratio rule controls for the same risks as does a Value-at-Risk (VaR) capital adequacy rule. Third, we argue that leverage ratio rules are better than VaR rules because they are more intuitive and easier to compare across firms.     

The Basel Committee proposals for a new capital accord: implications for Italian banks

Following a few general considerations on the recently proposed revision of the Basel Agreement on capital adequacy, this paper focuses on the first pillar of the Basel Committee proposals, the handling of capital requirements for credit risk in the banking book. The Basel Committee envisages an approach alternatively based on external ratings or on internal rating systems for the determination of the minimum capital requirement related to bank loan portfolios. This approach supports a system of capital requirements that is more sensitive to credit risk. On the basis of specific assumptions, these requirements provide a measure of the value at risk (VaR) produced by models used by major international banks. We first address the impact of the standardised and (internal ratings-based) IRB foundation approach using general data on Italian banks loans' portfolios default rates. We then simulate the impact of the proposed new rules on the corporate loan portfolios of Italian banks, using the unique data set of mortality rates recently published by the Bank of Italy. Three main conclusions emerge from the analysis: (i) the standardised approach implicitly penalizes Italian banks in their interbank funding as their rating is generally below AA/Aa, (ii) the average default rate experienced by Italian banks is higher than the one implied in the benchmark risk weight (BRW) proposed by the Basel Committee for the IRB foundation approach, thereby potentially leading to an increase in the regulatory risk weights, and (iii) the risk-weight is based on an average asset correlation that is significantly higher than the one historically recorded within the Italian banks' corporate borrowers. These findings support the need for a significant revision of the basic inputs and assumptions of the Basel proposals. Finally, in relation to the conditions that allow the capital market to effectively discipline banks, we comment on the proposals advanced in relation to the third pillar of the new capital adequacy scheme.     

On the Role of Regulatory Banking Capital

In this paper the authors study the role of regulatory banking capital and analyze the incentive effects of the Basel II Accord. They argue that Basel II may become a source of systemic risk due to endogenous risk and the risk sensitivity of the capital requirements. In this context they note that financial instability may enter via the asset side of the banks' balance sheets when banks are forced to sell assets in order to maintain the capital buffer prescribed by Basel II.     

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.     

The Effect of Bank Ownership Concentration on Capital Adequacy,Liquidity, and Capital Stability

We explore the effects of ownership concentration on the risk-taking behavior of banks. Our analysis focuses on East Asian countries because these nations have successfully implemented the Basel standards and demonstrate a high degree of regulatory convergence. For the period from 2005 to 2009, we analyzed the relation between ownership concentration and capital adequacy (Basel II) and find that an increase in ownership concentration by one standard deviation results in an improvement in capital adequacy by 7.64 %. Although Basel III does not go into effect until 2013, we retroactively apply the standards for capital stability on our sample. We find that ownership concentration would have been a significant determinant of capital stability. While at lower levels of ownership concentration, an increase in concentrated ownership would have reduced capital stability; at higher ownership levels, greater ownership concentration would have increased capital stability. We also find that concentrated ownership improves banks’ liquidity. Further, the recent financial crisis does not appear to change the fundamental associations among ownership concentration, capital adequacy, and liquidity.     

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.     

Implicit recourse and credit card securitizations: What do fraud losses reveal?

In this paper, we develop and test a model of implicit recourse in asset-backed securitizations. Fraud losses on securitized assets are generally incurred by the bank and do not affect the performance of securitization trusts, while credit losses do affect the trust’s performance and are potentially borne by the owner of the securitized assets. Thus, the classification of losses as either fraud or credit losses provides a potential avenue of implicit recourse to manipulate the performance of securitization trusts. Using annual data from 2001 to 2006, we find that the performance of the credit card securitization portfolio is negatively related to fraud losses reported by the bank. We examine these results in light of the proposed Basel II capital rules and argue that a bank’s incentive to provide implicit recourse will increase under the anticipated regime.     

Market crises and Basel capital requirements: Could Basel III have been different? Evidence from Portugal,Ireland, Greece and Spain (PIGS)

Basel III represents a crucial step in strengthening the capital rules underlying banking operations, aimed at reducing the probability and severity of a systemic crisis. Alongside two supplementary capital buffers, the Basel Committee of Banking Supervision imposed severe pressure on the Value-at-Risk based Internal Models Approach in order to increase. This is to increase the capital base by adding the stressed Value-at-Risk component in an effort to reduce reliance on internal models while keeping the Standardized Approach avenue open. However, even though those measures might appear theoretically correct, evidence gathered for long and short exposures in Portugal, Italy, Greece and Spain highlights several defects in Basel III. We emphasize that leptokurtic models, primarily those derived from Extreme Value Theory, should be enforced in the regulations given their superior performance in market crises, and that Basel II could have shielded against 2008 mayhem provided that heavy-tailed techniques had been employed.     

The impact of the choice of VaR models on the level of regulatory capital according to Basel II

The Basel II framework allows the calculation of the capital requirements for market risk with Value-at-Risk models. Since no special model is prescribed in the framework, banks may use simple models with questionable assumptions concerning their underlying distributions. Our numerical analysis reveals that simple VaR models that perform noticeably worse than comparable simple models with more realistic assumptions may lead to a lower level of regulatory capital for banks. For this reason, banks have a major incentive to implement bad models. This is obviously contrary to the interests of regulatory authorities.     

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.     

Credit risk in the leasing industry

This paper is devoted to the credit risk modeling issues of retail lease portfolios. Using a re-sampling method, I estimate the probability density function of losses and VaR measures in a portfolio of 46,732 leases issued between 1990 and 2000 by a major European financial institution. My results show that physical collaterals play a major role in reducing the credit risk associated with lease portfolios. However, because of insufficient recognition of such collaterals under the new regulatory capital framework (Basel II), significant differences are observed between the estimated capital requirements and those calculated in accordance with the various Basel II approaches.     

Bank Capital Regulation of Trading Portfolios: An Assessment of the Basel Framework

In setting minimum capital requirements for trading portfolios, the Basel Committee on Banking Supervision (1996, 2011a, 2013) initially used Value‐at‐Risk (VaR), then both VaR and stressed VaR (SVaR), and most recently, stressed Conditional VaR (SCVaR). Accordingly, we examine the use of SCVaR to measure risk and set these requirements. Assuming elliptically distributed asset returns, we show that portfolios on the mean‐SCVaR frontier generally lie away from the mean‐variance (M‐V) frontier. In a plausible numerical example, we find that such portfolios tend to have considerably higher ratios of risk (measured by, e.g., standard deviation) to minimum capital requirement than those of portfolios on the M‐V frontier. Also, we find that requirements based on SCVaR are smaller than those based on both VaR and SVaR but exceed those based on just VaR. Finally, we find that requirements based on SCVaR are less procyclical than those based on either VaR or both VaR and SVaR. Overall, our paper suggests that the use of SCVaR to measure risk and set requirements is not a panacea.     

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.     

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.     

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.     

The New Basel Capital Accord: Making it Effective with Stronger Market Discipline

In January 2001 the Basel Committee on Banking Supervision proposed a new capital adequacy framework to respond to deficiencies in the 1988 Capital Accord on credit risk. The main elements or 'pillars' of the proposal are capital requirements based on the internal risk-ratings of individual banks, expanded and active supervision, and information disclosure requirements to enhance market discipline. We discuss the incentive effects of the proposed regulation. In particular, we argue that it provides incentives for banks to develop new ways to evade the intended consequences of the proposed regulation. Supervision alone cannot prevent banks from 'gaming and manipulation' of risk-weights based on internal ratings. Furthermore, the proposed third pillar to enhance market discipline of banks' risk-taking is too weak to achieve its objective. Market discipline can be strengthened by a requirement that banks issue subordinated debt. We propose a first phase for introducing a requirement for large banks to issue subordinated debt as part of the capital requirement.     

An analysis of VaR-based capital requirements

We study the behavior of a financial institution subject to capital requirements based on self-reported VaR measures, as in the Basel Committee's Internal Models Approach. We view these capital requirements and the associated backtesting procedure as a mechanism designed to induce financial institutions to reveal the risk of their investments and to support this risk with adequate levels of capital. Accordingly, we consider the simultaneous choice of an optimal dynamic reporting and investment strategy. Overall, we find that VaR-based capital requirements can be very effective not only in curbing portfolio risk but also in inducing revelation of this risk.     

Backtesting value-at-risk based on tail losses

Extreme losses caused by leverage and financial derivatives highlight the need to backtest Value-at-Risk (VaR) based on the sizes of tail losses, because the risk measure currently used disregards losses beyond the VaR boundary. While Basel II backtests VaR by counting the number of exceptions, this paper proposes to use the saddlepoint technique by summing the sizes of tail losses. Monte Carlo simulations show that the technique is extremely accurate and powerful, even for small samples. Empirical applications for the proposed backtest find substantial downside tail risks in S&P 500, and demonstrate that risk models which account for jumps, skewed and fat-tailed distributions failed to capture the tail risk during the 1987 stock market crash. Finally, the saddlepoint technique is used to derive a multiplication factor for any risk capital requirement that is responsive to the sizes of tail losses.     

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.