Can regulators allow banks to set their own capital ratios?

Basel regulators have received widespread criticism for failing to prevent two credit crises that hit the U.S. over the last two decades. Nonetheless, banks were considerably overcapitalized prior to the onset of the 2007–2009 subprime crisis compared to those which had undergone the 1990–1991 recession. Therefore, if capital requirements were achieved prior to the subprime crisis, how could the Basel framework be blamed again for having accelerated if not caused another credit crunch? We find that the answer to this question lies in the relationship between the capital ratio and the leverage ratio which is governed by risk-weights categories determined by the Basel regulation. We show that changes to risk-weight categories which affect the correlation pattern between both ratios are not reflected in the subprime crisis. This minimizes the implication of the Basel II regulation in the crunch that succeeded its announcement, in contrast to Basel I. We demonstrate that these dynamics are governed by a formula linking the two ratios together which derives from the sensitivity of the risk-based capital ratio to a change in its risk-weight(s). One implication of our work regarding the Basel III regulation consists in validating the newly established capital increments in a mathematical rather than heuristical approach.     

Implications of bank regulation for loan supply and bank stability: a dynamic perspective

ABSTRACT

We show that internal funds play a particular role in the regulation of bank capital, which has not received much attention, yet. A bank's decision on loan supply and capital structure determines its immediate bankruptcy risk as well as the future availability of internal funds. These internal funds in turn determine a bank's future costs of external finance and its future vulnerability to bankruptcy risks. Using a partial equilibrium model, we study how internal funds affect these intra- and intertemporal links. Moreover, our positive analysis identifies the effects of risk-weighted capital-to-asset ratios, liquidity coverage ratios and regulatory margin calls on the dynamics of internal funds and thus loan supply and bank stability. Only regulatory margin calls or large liquidity coverage ratios achieve bank stability for all risk levels, but for large risks a bank will stop credit intermediation.     

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.     

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.     

Capital Allocation for Portfolio Credit Risk

Capital allocation rules are derived that maximize leverage while maintaining a target solvency rate for credit portfolios where risk is driven by a single common factor and idiosyncratic risk is fully diversified. Equilibrium conditions ensure that capital allocations depend on interest earnings as well as credits’ probability of default, endogenous loss given default, and asset correlation. Capitalization rates exceed those estimated using Gaussian credit loss models. Results demonstrate that credit risk is undercapitalized by the Basel II AIRB approach in part because of ambiguities regarding the definition of loss given default. An alternative proposed capital rule removes this bias.     

Risk-Based Capital and Credit Insurance Portfolios

This paper analyzes the risk-management practices of a vulnerable credit insurer by studying the effects of time-varying correlations, asset risks and loan maturities on the risk-based capital that backs credit insurance portfolios. Since asset correlations may change over a business cycle, we have analyzed these effects by means of a one-factor Gaussian stochastic model as part of an extended contingent claims analysis. Our results show the need to account for cyclical changes to correlations in the pricing of credit insurance. When compared with the reserve of risk-based capital recommended by the Basel II Internal Ratings-Based (IRB) approach, our model provides a better capital buffer against extreme credit losses, especially in times of recession and/or in a risky business environment. Using a risk-adjusted performance metric (RAPM), we find insurers perform better when insuring relatively short-term loans. We also make several policy recommendations on creating a reserve of risk-based capital to protect against possible loan losses.     

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.     

银行信贷、资本监管双重顺周期性与逆周期金融监管

商业银行信贷和资本监管具有顺周期性.银行信贷顺周期性导致经济繁荣时期的贷款扩张和经济衰退时的贷款紧缩.<巴塞尔资本协议Ⅱ>下的资本监管约束,在经济衰退时会促使银行形成信贷萎缩效应,影响和制约货币政策有效性的发挥,次贷危机为<巴塞尔资本协议Ⅱ>下的银行风险管理和监管的创新带来了新的要求和挑战.要减轻顺周期的影响,增强金融...     

Earnings and capital management and signaling: the use of loan-loss provisions by European banks

This paper investigates the relationship between loan-loss provisions (LLPs) and earnings management in the context of the capital adequacy of Euro Area (EA) banks versus non-EA credit institutions. This paper also examines whether LLPs signal managements’ expectations concerning future bank profits to investors. Additionally, this paper traces the role of bank regulations and creditor protection systems in explaining income smoothing. Evidence drawn from the 1996 to 2006 period indicates that LLPs do reflect changes in the expected quality of a bank's loan portfolio for both groups of banks, and that earnings management is an important determinant of LLPs for EA intermediaries, whereas non-EA credit institutions use LLPs to signal private information to outsiders. The paper also finds that higher protection of creditors’ rights significantly reduces the incentives to smooth earnings for EA banks. During the recent financial crisis, EA bank managers are much more concerned with their credit portfolio quality and do not use LLPs for discretionary purposes, whereas LLPs at non-EA banks are used to smooth income more than for the purposes of managing capital ratios or conveying private information about future performance to the market.     

Extending the Basel II approach to estimate capital requirements for equity investments

Under the Basel II banking regulatory capital regime the capital requirements for credit exposures are calculated using the Asymptotic Single Risk Factor (ASRF) approach. The capital requirement is taken to be the contribution of an exposure to the unexpected loss on the bank’s diversified portfolio. Here we extend this approach to calculate capital requirements for equity investments. We show that in the case when asset values have a normal distribution an analytical formula for the unexpected loss contribution may be developed. We show that the capital requirements for equity investments are quite different to those of credit exposures, since equity investments can suffer substantial loss of value even when the underlying company has not defaulted.     

Credit Risk Versus Capital Requirements under Basel II: Are SME Loans and Retail Credit Really Different?

Under Basel II, retail and SME credit (R&SME) receive special treatment because of a supposedly smaller exposure to systemic risk. Most research on this issue has been based on parameterized credit risk models. We present new evidence by applying Carey's (Carey, Mark. “Credit Risk in Private Debt Portfolios.” Journal of Finance 53, no. 4 (1998), 1363–1387.) nonparametric Monte-Carlo resampling method to two banks' complete loan portfolios. By exploiting that a sub-sample of all borrowers has been assigned an internal rating by both banks, we can compare the credit loss distributions for the three credit types, and compute both economic and regulatory capital under Basel II. We also test if our conclusions are sensitive to the definitions of R&SME credit. Our findings show that R&SME portfolios are usually riskier than corporate credit. Special treatment under Basel II is thus not justified. JEL classification: C14, C15, G21, G28, G33.     

Credit contagion in the presence of non-normal shocks

We generalize existing structural credit risk models that account for contagion effects across economic sectors, to capture the impact of neglected skewness and excess kurtosis in the asset return process, on the shape of the credit loss distribution. We specify Skew-Normal and Skew-Student t densities for the underlying asset return process and estimate the derived credit loss density using sector default rates based on proprietary data from the Central Bank of Mexico for six firm sectors. We show that, out of the six sectors analyzed, there is a significant contagion effect in ‘Commerce’, ‘Services’ and ‘Transport’. Moreover, we show that the non-Gaussian modelling of the common factor provides a better characterization than its Gaussian counterpart for the ‘Services’ sector. This result has a significant impact on the shape and the corresponding Value-at-Risk levels of the ‘Services’ credit loss distribution. In this context, traditional Basel and vendor-based credit risk models are inadequate as these do not consider the individual or the joint impact of contagion and non-Gaussian asset returns.     

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.     

Why is credit-to-GDP a good measure for setting countercyclical capital buffers?

We examine banks’ loan losses in Europe in 1982–2012 using a nonlinear three-factor model that takes into account output growth, real interest rate, and the ratio of private credit to GDP relative to its trend (i.e., “excessive indebtedness”). We find that a drop in output has an intensified impact on loan losses if the private sector is excessively indebted. Because increased bank credit risk should be matched with higher bank capital, the result motivates the Basel III's countercyclical capital buffers as a function of private indebtedness relative to its trend. The result also helps to explain differences in the amount of loan losses in different recessions across time and across countries. The model also indicates that low interest rates during the recent recession have clearly mitigated loan losses.     

The credit quality channel: Modeling contagion in the interbank market

We propose an algorithm to model contagion in the interbank market via what we term the “credit quality channel”. In existing models on contagion via interbank credit, external shocks to banks often spread to other banks only in case of a default. In contrast, shocks are transmitted also via asset devaluations and deteriorations in the credit quality in our algorithm. First, the probability of default (PD) of those banks directly affected by some shock increases. This increases the expected loss of the credit portfolios of the initially affected banks’ counterparties, thereby reducing the counterparties’ regulatory capital ratio. From a logistic regression we estimate the increase in the counterparties’ PD due to a reduced capital ratio. Their increased PDs in turn affect the counterparties’ counterparties, and so on. This coherent and flexible framework is applied to the bilateral interbank credit exposure of the entire German banking system in order to examine policy questions. For that purpose, we propose to measure the potential cost of contagion of a given shock scenario by the aggregated regulatory capital loss computed in our algorithm.     

Incorporating the dynamics of leverage into default prediction

A firm’s current leverage ratio is one of the core characteristics of credit quality used in statistical default prediction models. Based on the capital structure literature, which shows that leverage is mean-reverting to a target leverage, we forecast future leverage ratios and include them in the set of default risk drivers. An out-of-sample analysis of default predictions from a hazard model reveals that the discriminative power increases substantially when leverage forecasts are included. We further document that credit ratings contain information beyond the one contained in standard variables but that this information is unrelated to forecasts of leverage ratios.     

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.     

Regulatory and “economic” solvency standards for internationally active banks

One of the most important policy issues for financial authorities is to decide at what level average capital charges should be set. The decision may alternatively be expressed as the choice of an appropriate survival probability for representative banks over a horizon such as a year, often termed a “solvency standard”. This article sheds light on the solvency standards implied by current and possible future G10 bank regulation and on the “economic solvency standard” that banks choose themselves by their own capital setting decisions. In particular, we employ a credit risk model to show that the survival probability implied by the 1988 Basel Accord is between 99.0% and 99.9%. We then demonstrate that if a new Basel Accord were calibrated to such a standard, it would not represent a binding constraint on banks' current operations since most banks employ a solvency standard higher than 99.9%. To show this, we employ a statistical analysis of bank ratings adjusted for the impact of official or other support as well as credit risk model calculations. Lastly, we advance a possible explanation for the conservative capital choices made by banks by showing that swap volumes are highly correlated with credit quality for given bank size. This suggests that banks' access to important credit markets like the swaps markets may provide a significant discipline in the choice of solvency standard.     

A practical approach to validating a PD model

The capital adequacy framework Basel II aims to promote the adoption of stronger risk management practices by the banking industry. The implementation makes validation of credit risk models more important. Lenders therefore need a validation methodology to convince their supervisors that their credit scoring models are performing well. In this paper we take up the challenge to propose and implement a simple validation methodology that can be used by banks to validate their credit risk modelling exercise. We will contextualise the proposed methodology by applying it to a default model of mortgage loans of a commercial bank in the Netherlands.     

Information content of credit ratings in pricing of future earnings

This paper examines whether credit ratings convey information about the firm’s future earnings to the capital markets. Using the future earnings response coefficient methodology, we find that the current stock returns of rated firms reflect more future earnings than do the stock returns of non-rated firms. We also find that the market reflect more future earnings in current returns for higher-rated firms. In addition, we present evidence that returns impound future earnings to a greater extent after a ratings initiation or upgrade. We empirically eliminate the possibility that our findings are driven by earnings smoothing, market liquidity or omitted default risk factors associated with ratings. Our results are robust to controlling for potential omitted variables, endogeneity bias, loss versus profit firms, and serial correlation of error terms. Overall, the evidence suggests that credit ratings help disseminate private information to reduce information uncertainty about the firm’s future profitability among market participants.