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.     

Stress testing credit risk: The Great Depression scenario

By employing Moody’s corporate default and rating transition data spanning the last 90 years we explore how much capital banks should hold against their corporate loan portfolios to withstand historical stress scenarios. Specifically, we will focus on the worst case scenario over the observation period, the Great Depression. We find that migration risk and the length of the investment horizon are critical factors when determining bank capital needs in a crisis. We show that capital may need to rise more than three times when the horizon is increased from 1 year, as required by current and future regulation, to 3 years. Increases are still important but of a lower magnitude when migration risk is introduced in the analysis. Further, we find that the new bank capital requirements under the so-called Basel 3 agreement would enable banks to absorb Great Depression-style losses. But, such losses would dent regulatory capital considerably and far beyond the capital buffers that have been proposed to ensure that banks survive crisis periods without government support.     

Securitization and systematic risk in European banking: Empirical evidence

Using a unique dataset of 592 cash and synthetic securitizations issued by 54 banks from the EU-15 plus Switzerland over the period from 1997 to 2007 this paper provides empirical evidence that credit risk securitization has a positive impact on the increase of European banks’ systematic risk. Baseline results hold when comparing estimated beta coefficients with a control group of similar non-securitizing banks. Building several sub-samples we additionally find that (a) the increase in systematic risk is more relevant for larger banks that repeatedly engage in securitization, (b) securitization is more important for small and medium financial institutions, (c) banks have a higher incentive to retain the larger part of credit risk as a quality signal at the beginning of the securitization business in Europe, and (d) the overall risk-shifting effect due to securitization is more distinct when the pre-event systematic risk is low.     

Bank capital buffer and portfolio risk: The influence of business cycle and revenue diversification

The relationship between macroeconomic developments and bank capital buffer and portfolio risk adjustments is relevant to assess the efficacy of newly created countercyclical buffer requirements. Using the U.S. bank holding company data over the period 1992:Q1–2011:Q3, we find a negative relationship between the business cycle and capital buffer. Our results offer some support for the Basel III agreements that countercyclical capital buffer in the banking sector is necessary to help the performance of the real economy during recessions. We find a robust evidence of inverse relationship between business cycle and bank default risk. Our analysis provides evidence of diversification benefits. The probability of insolvency risk decreases for diversified banks and banks with high revenue diversity achieve capital savings.     

The macroeconomic sources of systemic risk in the banking sectors of five new EU member states

Rapid credit growth has been one of the most pervasive developments in recent years in Central and Eastern Europe. Our estimates support the hypothesis that the growth of credit and the amount of available finance might harm banking performance and deteriorate non-performing loans (NPL) dynamics, most probably due to the overheating of economies in the five NMSs. The procyclicality of banking sector performance and high economic activities growth is a signal of an economy overheating and therefore a slowdown in economic activity is likely to accelerate the growth of the NPL ratio.     

Bank incentives and suboptimal lending decisions: Evidence from the valuation effect of bank loan announcements in Japan

Using a sample of bank loan announcements in Japan, we examine whether or not banks have incentives to engage in suboptimal lending that results in wealth transfer from the banks to the borrowing firms. We find that abnormal returns for borrowing firms are significantly positive, but those for lending banks are sometimes significantly negative. Furthermore, the announcement returns for borrowing firms are negatively related to those for lending banks, especially when poorly performing firms borrow from financially healthy (low-risk) banks. Our results suggest that the positive valuation effect of bank loan announcements for borrowing firms is mainly due to a wealth transfer from lending banks.     

Performance and Merton-type default risk of listed banks in the EU: A panel VAR approach

This paper provides empirical evidence that sheds new light into the dynamic interactions between risk and efficiency, a highly debated issue. First, we estimate three alternative measures of bank performance, by employing a directional distance function framework, along with a cost frontier and a profit function. As a second step, we calculate a Merton-type bank default risk. Then, we employ a panel VAR analysis, which allows the examination of the underlying relationships between efficiency and risk without applying any a priori restrictions. Most evidence shows that the effect of a one standard deviation shock of the distance to default on inefficiency is negative and substantial. There is some evidence of a reverse causation. As part of a sensitivity analysis, we extent our study to investigate the relationship between efficiency and default risk for banks with different types of ownership structures and across financial systems with different levels of development.     

Understanding the rise and decline of the Japanese main bank system: The changing effects of bank rent extraction

This paper shows how main bank rent extraction affects corporate decisions about investment and financing during financial regulatory reform. Our model predicts that limited loanable funds can initially contain main bank controlled overinvestment, even when new equity is available to the firm. Abundant funds facilitate overinvestment to the detriment of firm profitability. A shift of control rights back to the firm due to financial deregulation produces an “equity for upside potential and bank debt for downside risk” bias against the banks. A stock market and real estate boom in Japan made it harder than ever for the banks to diversify risk. The insights from this analysis help explain why Japan’s main bank system was beneficial in the (capital constrained) postwar period but became harmful during the (capital abundant and even bubbly) 1980s, and why the adverse shocks of the post-deregulation 1990s had such severe effects on the banking system.     

Credit risk transfer activities and systemic risk: How banks became less risky individually but posed greater risks to the financial system at the same time

A main cause of the crisis of 2007-2009 is the various ways through which banks have transferred credit risk in the financial system. We study the systematic risk of banks before the crisis, using two samples of banks respectively trading Credit Default Swaps (CDS) and issuing Collateralized Loan Obligations (CLOs). After their first usage of either risk transfer method, the share price beta of these banks increases significantly. This suggests the market anticipated the risks arising from these methods, long before the crisis. We additionally separate this beta effect into a volatility and a market correlation component. Quite strikingly, this decomposition shows that the increase in the beta is solely due to an increase in banks’ correlations. Thus, while banks may have shed their individual credit risk, they actually posed greater systemic risk. This creates a challenge for financial regulation, which has typically focused on individual institutions.     

Deposit insurance coverage,ownership, and banks' risk-taking in emerging markets

We ask how deposit insurance systems and ownership of banks affect the degree of market discipline on banks' risk-taking. Market discipline is determined by the extent of explicit deposit insurance, as well as by the credibility of non-insurance of groups of depositors and other creditors. Furthermore, market discipline depends on the ownership structure of banks and the responsiveness of bank managers to market incentives. An expected U-shaped relationship between explicit deposit insurance coverage and banks' risk-taking is influenced by country specific institutional factors, including bank ownership. We analyze specifically how government ownership, foreign ownership and shareholder rights affect the disciplinary effect of partial deposit insurance systems in a cross-section analysis of industrial and emerging market economies, as well as in emerging markets alone. The coverage that maximizes market discipline depends on country-specific characteristics of bank governance. This “risk-minimizing” deposit insurance coverage is compared to the actual coverage in a group of countries in emerging markets in Eastern Europe and Asia.     

Diversification and Value-at-Risk

A pervasive and puzzling feature of banks’ Value-at-Risk (VaR) is its abnormally high level, which leads to excessive regulatory capital. A possible explanation for the tendency of commercial banks to overstate their VaR is that they incompletely account for the diversification effect among broad risk categories (e.g., equity, interest rate, commodity, credit spread, and foreign exchange). By underestimating the diversification effect, bank’s proprietary VaR models produce overly prudent market risk assessments. In this paper, we examine empirically the validity of this hypothesis using actual VaR data from major US commercial banks. In contrast to the VaR diversification hypothesis, we find that US banks show no sign of systematic underestimation of the diversification effect. In particular, diversification effects used by banks is very close to (and quite often larger than) our empirical diversification estimates. A direct implication of this finding is that individual VaRs for each broad risk category, just like aggregate VaRs, are biased risk assessments.     

Ownership structure, market discipline, and banks’ risk-taking incentives under deposit insurance

The paper studies the effects of market discipline by creditors and ownership structure on banks’ risk taking in the presence of partial deposit insurance. An agency-cost model explains how the effects of creditor discipline and shareholder control are interdependent, the non-monotonic effect of shareholder control, and the role of leverage. Panel regressions on several hundred banks worldwide 1995-2005 confirm a negative individual risk effect of creditor discipline and the expected convex effect of shareholder control. Increased shareholder control significantly strengthens the negative effect of market discipline on asset risk, but joint effects on overall default risk are limited.     

Asymmetric information and liquidity constraints: A new test

Using a novel measure of the degree of information asymmetry across firms, this study shows that information-related financial market imperfections do matter for a firm’s access to external finance. Prior studies of the importance of liquidity constraints faced by nonfinancial firms have suffered from a glaring weakness. They have been based on a sample of publicly traded firms, omitting precisely those firms most likely to be liquidity constrained. Furthermore, they have tended to rely on indirect measures of the degree of information asymmetry, such as firm size. We overcome these limitations by focusing on the banking sector. Unlike the nonfinancial sector, the banking sector has balance sheet and income data available for all firms, whether or not they are publicly traded. This allows the use of a superior measure of the degree of information asymmetry across firms by distinguishing between publicly traded and non-publicly traded banks.     

Do banks overstate their Value-at-Risk?

This paper is the first empirical study of banks’ risk management systems based on non-anonymous daily Value-at-Risk (VaR) and profit-and-loss data. Using actual data from the six largest Canadian commercial banks, we uncover evidence that banks exhibit a systematic excess of conservatism in their VaR estimates. The data used in this paper have been extracted from the banks’ annual reports using an innovative Matlab-based data extraction method. Out of the 7354 trading days analyzed in this study, there are only two exceptions, i.e. days when the actual loss exceeds the disclosed VaR, whereas the expected number of exceptions with a 99% VaR is 74. For each sample bank, we extract from historical VaRs a risk-overstatement coefficient, ranging between 19 and 79%. We attribute VaR overstatement to several factors, including extreme cautiousness and underestimation of diversification effects when aggregating VaRs across business lines and/or risk categories. We also discuss the economic and social cost of reporting inflated VaRs.     

Private equity and regulatory capital

Regulatory capital requirements for European banks have been put forward in the Basel II Capital Framework and subsequently in the capital requirements directive (CRD) of the EU. We provide a detailed discussion of the capital requirements for private equity investments under different approaches. For the internal model approach we present a structural model that we calibrate to a proprietary dataset. We modify the standard Merton structural model to make it applicable in practice and to capture stylized facts of private equity investments. We also implement the early default feature with a fast simulation algorithm. Our results support capital requirements lower than in Basel II, but not as low as in CRD, thereby giving adverse incentives to banks for using advanced risk models. A sensitivity analysis shows that this finding is robust to parameter uncertainty and stress scenarios.     

“When the cat's away the mice will play”: Does regulation at home affect bank risk-taking abroad?

This paper provides the first empirical evidence that bank regulation is associated with cross-border spillover effects through the lending activities of large multinational banks. We analyze business lending by 155 banks to 9,613 firms in 1,976 different localities across 16 countries. We find that lower barriers to entry, tighter restrictions on bank activities, and to a lesser degree higher minimum capital requirements in domestic markets are associated with lower bank lending standards abroad. The effects are stronger when banks are less efficiently supervised at home, and are observed to exist independently from the impact of host-country regulation.     

Are Bank Holding Companies a Source of Strength to Their Banking Subsidiaries?

I document evidence that a bank affiliated with a multi-bank holding company (MBHC) is significantly safer than either a stand-alone bank or a bank affiliated with a one-bank holding company. Not only does MBHC affiliation reduce the probability of future financial distress, but distressed affiliated banks are also more likely to receive capital injections, recover more quickly, and are less likely to fail over the next year. Moreover, the measured benefits of affiliation are much larger than those that existed before recent reforms of bank holding company regulation, suggesting that much of the observed benefit can be attributed to regulation and not the market.     

Contingent convertibles. Solving or seeding the next banking crisis?

A recent proposal to enhance banking stability recommends the use of contingent convertibles (CoCos). Since these hybrid securities are mandatorily converted into equity when banks are in need of a recapitalization, they are credited for reducing banks’ likelihood of financial distress. In this paper, we show within a continuous-time framework that this allegedly beneficial impact hinges critically on the assumption of complete contracts. If contracts are incomplete in the sense that manager-owners enjoy discretion over the risk of the investment program, our analysis shows that CoCo bonds always distort risk taking incentives. Our main contribution is to demonstrate that there exist conditions under which CoCo bond financing increases investors’ wealth, but also increases the bank’s probability of financial distress, so that the banking system as a whole will be destabilized. Thus, individually rational decisions can have systemically undesirable outcomes. Further results indicate that CoCos should be used only in conjunction with devices to control risk shifting incentives.