The impact of imposing capital requirements on systemic risk

This paper examines the impact of imposing capital requirements on systemic risk. We use a static model on financial institutions’ risk-taking behavior to quantify the systemic risk in the cross-sectional dimension in both regulated and unregulated systems. Although imposing a capital requirement can lower individual risk, it simultaneously enhances systemic linkage within the system. By using a proper systemic risk measure combining both individual risk and systemic linkage, we show that systemic risk in a regulated system can be higher than that in an unregulated system. In addition, we analyze a sufficient condition under which the systemic risk in a regulated system is always lower.     

Dynamics of Banks' Capital Accumulation

We construct a dynamic neoclassical model of banking capital where the dynamics are governed by the process of financial capital accumulation and credit risk realizations in a structure where stylized banking characteristics are maintained. This is aimed at focusing on how the profit‐maximizing capital ratio of banks evolves and how it reacts to exogenous shocks particularly so during periods of prolonged downturn of the economy. We examine impulse responses of our model to credit risk shock, business cycle shock, and monetary policy shock. The convergence of financial capital to its optimal level is also explored.     

The regulator’s trade-off: Bank supervision vs. minimum capital

We develop a simple model of banking regulation with two policy instruments: minimum capital requirements and the supervision of domestic banks. The regulator faces a trade-off: high capital requirements cause a drop in the banks’ profitability, whereas strict supervision reduces the scope of intermediation and is costly for taxpayers. We show that a mix of both instruments minimises the costs of preventing the collapse of financial intermediation. Once we allow for cross-border banking, the optimal policy is not feasible. If domestic supervisory effort is not observable, our model predicts a race to the bottom in capital requirement regulation. Therefore, countries are better off by harmonising regulation on an international standard.     

Systemic risk and diversification across European banks and insurers

The mutual and cross company exposures to fat-tail distributed risks determine the potential impact of a financial crisis on banks and insurers. We examine the systemic interdependencies within and across the European banking and insurance sectors during times of stress by means of extreme value analysis. While insurers exhibit a slightly higher interdependency in comparison with banks, the interdependency across the two sectors turns out to be considerably lower. This suggests that downside risk can be lowered through financial conglomeration.     

An Alternative View on Regulatory Distortions in a Competitive Financial Services Industry

We present an alternative view on regulatory distortions in the banking industry. We use the duopoly model developed by Boot, Dezelan, and Milbourn (BDM, 2000), where a bank with low monitoring costs faces a bank with high monitoring costs. We show that when the initial level of the capital requirement is low, an increase of the minimum ratio between capital and total assets causes a higher decrease in profits at the bad bank than at the good bank. This finding contrasts with BDM's theorem 1, which predicts that a regulation imposing an identical increase in production costs on both banks will cause a greater loss in profits at the good bank than at the bad bank. We also look at the impact of an increase in the minimum ratio between capital and total assets on the profits of a representative bank in three other competitive environments identified in BDM. We find that the decrease in the representative bank's profit caused by an increase in the capital requirement is larger when the bank faces competition from an unregulated firm than when it faces a regulated competitor or no competitor at all. This result is consistent with BDM's theorem 2.     

资本监管、风险承担与货币政策传导机制——研究综述与展望

频频爆发的银行危机暴露了以资本监管为核心的巴塞尔协议的内在缺陷,学术界就资本监管的微观效应和宏观效应展开了激烈的讨论.从文献研究的角度,通过回顾和分析理论界关于资本监管、银行风险承担和货币政策传导机制三者之间复杂关系的研究,可以看出,在微观意义上,关于资本监管对银行风险承担行为影响的研究忽视了对资本监管框架效应的分析;在宏观意义上,资本监管的强化给货币政策传导机制带来了新的渠道,即银行资本渠道和风险承担渠道.这两种新的传导机制在后金融危机时代,是研究宏观审慎监管框架下货币政策效应的核心命题.     

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.     

Margining in derivatives markets and the stability of the banking sector

We investigate the effects of margining, a widely-used mechanism for attaching collateral to derivatives contracts, on derivatives trading volume, default risk, and on the welfare in the banking sector. First, we develop a stylized banking sector equilibrium model to develop some basic intuition of the effects of margining. We find that a margin requirement can be privately and socially sub-optimal. Subsequently, we extend this model into a dynamic simulation model that captures some of the essential characteristics of over-the-counter derivatives markets. Contrarily to the common belief that margining always reduces default risk, we find that there exist situations in which margining increases default risk, reduces aggregate derivatives’ trading volume, and has an ambiguous effect on welfare in the banking sector. The negative effects of margining are exacerbated during periods of market stress when margin rates are high and collateral is scarce. We also find that central counterparties only lift some of the inefficiencies caused by margining.     

论银行市场风险的资本计提——兼评内部模型法的适用性

市场风险及其监管资本要求的计量历来为业界和监管当局所关注。近期,次贷危机爆发导致的市场动荡使得全球银行业和监管当局开始重新审视其市场风险管理和监管资本要求。文章结合国际银行业和监管机构计量市场风险及其监管资本要求的当前做法,针对我国银行业的实际情况,重点探索了内部模型法在我国银行业的适用性,尤其是从方法论、特殊风险计量、验证等角度探讨了内部模型法的主要工具——风险价值体系在我国银行业计量市场风险及其监管资本要求的适用性,并从方法论和应用层面提出了相应的政策建议。     

Transatlantic systemic risk

In this paper we study systemic risk for the US and Europe. We show that banks’ exposures to common risk factors are crucial for systemic risk. We come to this conclusion by first showing that relations between US and European banks are smaller than within each region. We then show that European banks react more strongly to the onset of the financial crisis than US banks. Regarding the consequences of systemic risk, we show that dependence between the banking sector and a wide range of real sectors is limited. Our results imply that regulators and supervisors should address international bank dependencies arising from common risk factors, while recessions in real sectors due to bank defaults should be a secondary concern.     

Credit risk transfer and contagion

Some have argued that recent increases in credit risk transfer are desirable because they improve the diversification of risk. Others have suggested that they may be undesirable if they increase the risk of financial crises. Using a model with banking and insurance sectors, we show that credit risk transfer can be beneficial when banks face uniform demand for liquidity. However, when they face idiosyncratic liquidity risk and hedge this risk in an interbank market, credit risk transfer can be detrimental to welfare. It can lead to contagion between the two sectors and increase the risk of crises.     

Contagion risk in the Australian banking and property sectors

The Australian banking system emerged from the global crisis virtually unhurt, with most banks still profitable, adequately capitalized, and with AA credit ratings. Are there any risks or vulnerabilities in this success story? This paper analyzes Australia’s systemic banking risk and attempts to determine if this risk increased with the recent global crisis and whether this risk is related to the downturn experienced in the real estate market. We use extreme value theory to measure banks’ and property firms’ univariate Value at Risk, as well as multivariate intra-sector and inter-sector contagion risks. Of the 13 sectors analyzed, we find that the property sector exhibits the highest level of extremal dependence with the banking sector. The credit crisis significantly increased the probability of a bank or property firm crashing. Moreover, contagion risks significantly increased not only within the banking and property sectors, but also between those sectors.     

Credit supply and corporate innovation

We present evidence that banking development plays a key role in technological progress. We focus on manufacturing firms' innovative performance, measured by patent-based metrics, and employ exogenous variations in banking development arising from the staggered deregulation of banking activities across US states during the 1980s and 1990s. We find that interstate banking deregulation had significant beneficial effects on the quantity and quality of innovation activities, especially for firms highly dependent on external capital and located closer to entering banks. Furthermore, we find that these results are strongly driven by a greater ability of deregulated banks to geographically diversify credit risk.     

The size of banking crises in credible fixed exchange rate regimes

Since monetary policy is constrained in fixed exchange rate regimes, we should observe fewer banking crises due to moral hazard in countries with credible currency pegs. However, three countries with seemingly credible pegs in the nineteen-eighties and -nineties, namely China, Hong Kong and Argentina, still suffered crises in their domestic banking sectors. The present note illustrates that bank incentives to take on excess risk still exist in countries with currency peg credibility and that the size of that risk exposure (and thus the potential for crisis) may be positively related to the level of central bank foreign exchange reserves.     

How does capital affect bank performance during financial crises?

This paper empirically examines how capital affects a bank’s performance (survival and market share) and how this effect varies across banking crises, market crises, and normal times that occurred in the US over the past quarter century. We have two main results. First, capital helps small banks to increase their probability of survival and market share at all times (during banking crises, market crises, and normal times). Second, capital enhances the performance of medium and large banks primarily during banking crises. Additional tests explore channels through which capital generates these effects. Numerous robustness checks and additional tests are performed.     

Does Macro‐Prudential Regulation Leak? Evidence from a UK Policy Experiment

The regulation of bank capital as a means of smoothing the credit cycle is a central element of forthcoming macro‐prudential regimes internationally. For such regulation to be effective in controlling the aggregate supply of credit it must be the case that: (i) changes in capital requirements affect loan supply by regulated banks, and (ii) unregulated substitute sources of credit are unable to offset changes in credit supply by affected banks. This paper examines micro evidence—lacking to date—on both questions, using a unique data set. In the UK, regulators have imposed time‐varying, bank‐specific minimum capital requirements since Basel I. It is found that regulated banks (UK‐owned banks and resident foreign subsidiaries) reduce lending in response to tighter capital requirements. But unregulated banks (resident foreign branches) increase lending in response to tighter capital requirements on a relevant reference group of regulated banks. This “leakage” is substantial, amounting to about one‐third of the initial impulse from the regulatory change.     

Time‐Varying Capital Requirements and Disclosure Rules: Effects on Capitalization and Lending Decisions

We investigate how banks’ capital and lending decisions respond to changes in bank‐specific capital and disclosure requirements. We find that an increase in the bank‐specific regulatory capital requirement results in a higher bank capital ratio, brought about via less asset risk. A decrease in the requirement implies more lending to firms but also less Tier 1 capital and higher bank leverage. We do not observe differences between confidential and public disclosure of capital requirements. Our results empirically illustrate a tradeoff between bank resilience and a fostering of the economy through more bank lending using banks’ capital requirement as policy instrument.     

The asymmetric behavior and procyclical impact of asset correlations

This paper examines the behavior of asset correlations with the market returns in the asymptotic single risk factor (ASRF) approach of the Basel II accord on regulatory capital requirement. Over a sample period from 1988 to 2007, we find that asset correlations are positively related to firm size, but negatively related to firm default probability. Asset correlations are also industry specific, as firms in media, transportation, pharmaceutical, and semiconductor industries exhibit higher asset correlations than those in retail and consumer staples. Most importantly, asset correlations are asymmetric and have a procyclical impact on the real economy after controlling for these effects. They tend to rise during economic downturns, but decline during economic upturns. The average magnitude of the rise is larger than that of the decline. These findings suggest that asset correlations may be underestimated during economic downturns, and may provide policy implications for the capital requirement framework.     

The pernicious effects of contaminated data in risk management

Banks hold capital to guard against unexpected surges in losses and long freezes in financial markets. The minimum level of capital is set by banking regulators as a function of the banks’ own estimates of their risk exposures. As a result, a great challenge for both banks and regulators is to validate internal risk models. We show that a large fraction of US and international banks uses contaminated data when testing their models. In particular, most banks validate their market risk model using profit-and-loss (P/L) data that include fees and commissions and intraday trading revenues. This practice is inconsistent with the definition of the employed market risk measure. Using both bank data and simulations, we find that data contamination has dramatic implications for model validation and can lead to the acceptance of misspecified risk models. Moreover, our estimates suggest that the use of contaminated data can significantly reduce (market-risk induced) regulatory capital.     

Bank regulation and international financial stability: A case against the 2006 Basel framework for controlling tail risk in trading books

In attempting to promote international financial stability, the Basel Committee on Banking Supervision (2006) provided a framework that sought to control the amount of tail risk that large banks around the world would take in their trading books relative to their corresponding minimum capital requirements. However, many of these banks suffered significant trading losses during the recent financial crisis. Our paper examines whether the Basel framework allowed banks to take substantive tail risk in their trading books without a capital requirement penalty. We find that it allowed banks to do so and that its minimum capital requirements can be notably procyclical. Hence, focusing on the way the Basel framework sought to control the amount of tail risk in trading books relative to their corresponding minimum capital requirements, our paper supports the view that it was not properly designed to promote financial stability. We also discuss alternative regulatory frameworks that would potentially be more effective than the Basel framework in preventing banks from taking substantive tail risk in their trading books without a capital requirement penalty.