Can banks default overnight? Modelling endogenous contagion on the O/N interbank market

We propose a new model of the liquidity-driven banking system focusing on overnight interbank loans. This significant branch of the interbank market is commonly neglected in the banking system modelling and systemic risk analysis. We construct a model where banks are allowed to use both the interbank and the securities markets to manage their liquidity demand and supply as driven by prudential requirements in a volatile environment. The network of interbank loans is dynamic and simulated every day. We show how the intrasystem cash fluctuations alone, without any external shocks, may lead to systemic defaults, and what may be a symptom of the self-organized criticality of the system. We also analyze the impact of different prudential regulations and market conditions on the interbank market resilience. We confirm that the central bank’s asset purchase programmes, limiting the declines in government bond prices, can successfully stabilize banks’ liquidity demands. The model can be used to analyze the interbank market impact of macroprudential tools.     

Assessing systemic risk using interbank exposures in the global banking system

This paper contributes to the literature on systemic risk by examining the network structure of bilateral exposures in the global banking system. The global interbank market constitutes a major part of the global banking system. The market has a hierarchical network structure, composed of the national or jurisdictional area's local markets and the cross-border interbank market. First, we estimate the bilateral exposures matrix using aggregate financial data on loans and deposits from Bankscope and analyze the interconnectedness in the market using network centrality measures. Subsequently, for the model analysis, we apply the Eisenberg–Noe framework to a multi-period setting. In this framework, bank defaults are classified into stand-alone defaults and contagious defaults. The banks in our sample (i.e., the top 202 banks with more than $50 billion in total assets) comprise a major part of this global banking system. The main findings are as follows: The theoretical network analysis using network centrality measures showed that most of the banks designated as global systemically important banks (G-SIBs) play a central role in the global interbank market. The theoretical default analysis showed a few contagious defaults triggered by the basic defaults during and after the global financial crisis. Our stress test proved that many G-SIBs theoretically caused 1–6 contagious defaults. Our methodology would assist in the development of a monitoring system by the respective supervisory authorities as well as in the implementation of bank-internal stress tests of default contagion.     

Social networks in the global banking sector

We show that banks with shared social connections partner more often in the global syndicated loan market and that central banks in the network play dominant roles in various interbank transactions, indicating that social connections facilitate business connections. However, more centralized banks in the network also contribute significantly to the global systemic risk. Moreover, we find the soft information generated by social networks is particularly valuable when potential partners operate under different accounting and regulatory standards. Finally, we show that the recent banking crisis significantly limited the positive soft information effects of social networks in the global banking system.     

Can the U.S. Interbank Market Be Revived?

The U.S. interbank market essentially disappeared as the reserve supply dramatically increased after the 2007–2008 crisis. We build a model to study whether the interbank market can revive if the reserve supply decreases sufficiently. The market may not revive due to balance sheet costs associated with recent banking regulations. Although interbank volume may initially increase as reserves decline from abundant levels, the balance sheet costs may engender changes in market structure that completely replace interbank trading by nonbank lending to banks. This nonmonotonic response could lead to misleading forecasts about future interbank volumes.     

Interbank tiering and money center banks

This paper provides evidence that interbank markets are tiered rather than flat, in the sense that most banks do not lend to each other directly but through money center banks acting as intermediaries. We capture the concept of tiering by developing a core-periphery model, and devise a procedure for fitting the model to real-world networks. Using Bundesbank data on bilateral interbank exposures among 2000 banks from 1999 to 2012, we find strong evidence of tiering in the German banking system. This extent of tiering is unlikely to arise in standard random networks. Indeed, we show that bank specialization and balance sheet variables predict how banks position themselves in the interbank market. This link provides a promising avenue for understanding the formation of financial networks.     

Have changes in the financial structure affected bank profitability? Evidence for Austria

We examine the impact of changes in the financial structure of the Austrian banking sector over the past 15 years, such as disintermediation, internationalization and privatization, on the profitability of banks. Several proxies based on bank balance sheet data at the micro-level as well as macroeconomic variables are used to capture these changes. The case of Austria is particularly interesting because the opening up of the Austrian banking sector due to EU accession and the strong engagement of Austrian banks in Eastern Europe coincided with the global trend toward deregulation of banking activities. Our estimation results, which are based on dynamic panel regression methods, indicate that disintermediation (a lower percentage of loans over total assets) and higher market concentration in the banking sector had a positive effect on bank profitability, while changes in the ownership structure (privatization and increased foreign ownership) as well as more foreign lending by Austrian banks did not have a clear-cut or significant impact on bank profits.     

International business: determinants of interbank activities

This paper investigates the determinants of the international interbank market, a significant component of international trade in financial services. The sample encompasses both monthly and quarterly data from 1983 to 1993. The superiority of the monthly results suggest that the interbank market should be modelled within a short-term framework. This data interval captures the short-term movement of funds between currencies, Eurobonds, the nonbank market and the domestic banking market by banks to maximize returns. Moreover, the interbank market does not necessarily move in line with fundamental trade and income variables. Rather, the market is sensitive to return differentials, the relative cost of capital, the yield curve and international nonbank assets. The empirical results also indicate that nationality remains important in interbank trading because of the advantages it imparts on the home country in dealing in its home currency, particularly if that currency is a vehicle currency.     

A Model of Systemic Bank Runs

We develop a tractable model of systemic bank runs. The market-based banking system features a two-layer structure: banks with heterogeneous fundamentals face potential runs by their creditors while they trade short-term funding in the asset (interbank) market in response to creditor withdrawals. The possibility of a run on a particular bank depends on its assets' interim liquidation value, and this value depends endogenously in turn on the status of other banks in the asset market. The within-bank coordination problem among creditors and the cross-bank price externality feed into each other. A small shock can be amplified into a systemic crisis.     

A network model of systemic risk: stress testing the banking system1

Although there are many definitions of systemic risk, most agree that it manifests itself by an initial shock that results in the failure of one or more banks and then spreads out to the entire system by a contagion mechanism which can result in the failure of more banks in the system. Assuming that bank failures in the initial shock are randomly dependent on the failure probabilities of the individual banks and that the ensuing contagion process is deterministic, depending on interbank exposures, in this paper we propose a network model to analyse systemic risk in the banking system that, in contrast to other proposed models, seeks to obtain the probability distribution of losses for the financial system resulting from the shock/contagion process. Thus, calculating the probabilities of joint failures by simulation and assuming that the matrix of bilateral interbank exposures is known, we represent systemic risk in the financial system by means of a graph and use discrete modelling techniques to characterize the dynamics of contagion and corresponding losses within the network. The probability distribution of losses, risk profile for the Mexican banking system, is obtained through an efficient, complete enumeration procedure of all possible bank default events in the system. This, in turn, allows the use of the wide variety of well-established risk measures to describe the fragility of the financial system. Additionally, the model allows us to perform stress tests along both the bank default probabilities and the interbank exposures and is used to assess the risk of the Mexican banking system. Copyright © 2009 John Wiley & Sons, Ltd.     

资产透明度、监管套利与银行系统性风险

资产不透明的金融机构过度依赖批发性融资进行监管套利不利于系统性风险的防控。在此背景下,本文首先在经典银行道德风险模型的基础上引入关联性,从资产透明度和监管套利的视角分析银行系统性风险累积的内在机理。而后利用2007-2018年中国上市银行微观数据,构建资产透明度指标和系统性风险指标(SRISK、MES),对理论推论进行实证检验。主要结论有:(1)资产不透明、监管套利会提高银行的系统性风险。(2)监管套利弱化了资产透明度和资本监管机制对银行系统性风险承担的约束作用,资产透明度与资本监管机制在约束系统性风险承担中的协调作用不明显。(3)以大银行为主的债权银行受监管套利的影响相较于受资产透明度的影响更明显。在此基础上,我们对完善金融风险防范体系以及监管机制提出了若干建议。     

Systemic liquidity shortages and interbank network structures

This paper aims to shed light on the systemic nature of liquidity risk and to propose a method for calculating systemic liquidity shortages. Our method incorporates not only direct liquidity shortages but also indirect liquidity shortages due to the knock-on effects through interbank linkages. We perform a simulation with a simple banking system model and find that a deficit bank can mitigate a liquidity shortage by holding more claims on a surplus bank. Meanwhile, a greater imbalance in liquidity positions across banks tends to aggravate the liquidity shortage of a deficit bank. According to comparative analysis between different types of network structures, a core-periphery network with a deficit money center bank gives rise to the highest level of systemic liquidity shortage, and a banking system becomes more vulnerable to liquidity shocks as its interbank network becomes more ill-matched.     

(In)Efficient Interbank Networks

We study the efficiency properties of the formation of an interbank network. Banks face a trade-off by establishing connections in the interbank market. On the one hand, banks improve the diversification of their liquidity risk and therefore can obtain a higher expected payoff. On the other hand, banks not sufficiently capitalized have risk-shifting incentives that expose them to the risk of bankruptcy. Connecting to such risky banks negatively affects expected payoff. We show that both the optimal and the decentralized networks are characterized by a core-periphery structure. The core is made of the safe banks, whereas the periphery is populated by the risky banks. Nevertheless, the two network structures coincide only if counterparty risk is sufficiently low. Otherwise, the decentralized network is underconnected as compared to the optimal one. Finally, we analyze mechanisms that can avoid the formation of inefficient interbank networks.     

Correlated bank runs,interbank markets and reserve requirements

This article extends the application of global games of Goldstein and Pauzner (2005) in the banking model of Diamond and Dybvig (1983) to account for correlation in the quality of banks’ long term investment, when banks are linked through cross deposits and there is a central bank. The goal is to study how these elements affect the deposit contract that banks offer to depositors and the ex ante probability of a bank run. We show that the coexistence of a central bank, which determines banks’ reserve requirements, and an interbank market, which redistributes reserves, leads to a smaller probability of a bank run and to fewer inefficient bank runs, relative to the case with no central bank and no interbank market. By adequately choosing the level of reserves to store, the central bank can improve the equilibrium outcome and allow banks to offer a higher interim payment to depositors, relative to the situation with no cross deposits.     

Interbank contagion risk in China under an ABM approach for network formation

This paper uses an agent-based model to construct an interbank network for the Chinese interbank market using a sample of 299 commercial banks from 2014 to 2019. We analyze the importance and vulnerability of banks using the DebtRank algorithm. Our results show that the Chinese interbank market bears a certain level of systemic risk, especially among lower-tiered banks. The results also show a bank is more vulnerable if it has a higher interbank lending ratio and greater financial connectivity. Meanwhile, a bank is more influential if it has a larger net worth and greater financial connectivity.     

The interbank network across the global financial crisis: Evidence from Italy

This study examines the effects of the global financial crisis (GFC) on interbank market connectivity using network analysis. More specifically, using data on Italian banks’ bilateral interbank positions between 1998 and 2013, we analyze the impact of the following events on each bank's network centrality: the liquidity crisis in August 2007, the collapse of Lehman Brothers in September 2008, Eurosystem's long term refinancing operations (LTROs) between 2009 and 2012, the sovereign debt crisis in July 2011, and the announcement of Outright Monetary Transactions (OMT) in 2012. The results show that the 2007 liquidity crisis and especially the collapse of Lehman Brothers are associated with a marked reduction of the relative interconnectedness of the Italian banking sector (i.e., a shift in the distribution of banks’ centrality to the left, away from the most connected bank). In the following years, the system progressively recovered its initial patterns of integration among banks, which coincided with the main Eurosystem's monetary policy interventions. However, the average outcome conceals different results across banks, depending on their characteristics and initial positions within the system.     

2010年3季度银行间市场运行报告

2010年第三季度,银行间市场创新频出、整体运行平稳。银行间外汇市场引入人民币兑林吉特交易,支持跨境贸易人民币结算业务的发展;人民银行发布通知允许境外人民币清算行等三类机构进入银行间债券市场,拓宽人民币回流渠道;银行间市场贷款转让业务上线交易,丰富银行业金融机构主动管理资产的手段。第三季度,货币市场资金面复杂多变,短期货币市场利率波动明显,市场交易大幅增长;银行间国债指数继续上行,债券交易增长明显;外汇市场上人民币汇率连创新高,价格波动较大,市场交易趋于谨慎;利率和汇率衍生品市场整体保持较快发展。     

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.     

Banking industry volatility and banking crises

While studies using balance sheet information of banks and macroeconomic indicators to forecast banking crises are prolific, empirical research using market information of banks is relatively sparse. We investigate whether banking industry volatility, constructed with the disaggregated approach from Campbell et al. [Campbell, J.Y., Lettau, M., Malkiel, B.G., Xu, Y., 2001. Have individual stocks become more volatile? An empirical exploration of idiosyncratic risk? The Journal of Finance 56, 1–43] using exclusively publicly available market information of banks, is a good predictor of systemic banking crises in the analyses including data from 18 developed and 18 emerging markets. We find that banking industry volatility performs well in predicting systemic banking crises for developed markets but very poor for emerging markets, which suggest that the impact of market forces on the soundness of the banking system might be different for developed and emerging markets. We also find that those macroeconomic and banking risk management indicators have different impact on the probability of banking crises. Therefore, the traditional cross-country results of the studies on banking crises need to be interpreted cautiously.     

基于DCC-GARCH模型的中国上市银行系统性风险研究

以我国15家上市银行为研究对象,就银行间的风险联动关系进行研究。研究主要包括：上市银行收益率两两间的时变相关系数测算、4家大型国有商业银行与11家股份制商业银行间的整体相关程度的测算,以及根据我国上市银行间的动态相关关系构建银行体系风险联动的预警指标。研究发现：我国上市银行间普遍存在显著的非对称的动态相关关系,4家大型国有银行间的平均动态相关系数比他们和其余11家银行间的相关系数高;我国的4家大型国有商业银行与11家股份制商业银行的整体相关程度也很高;15家上市银行两两的动态条件相关系数序列构建的银行体系系统性风险预警指标能够及时检测市场风险。     

Interbank Credit Lines as a Channel of Contagion

This paper assesses the potential for contagion in the Swiss interbank market using new data on bilateral bank exposures as well as on credit lines. A simulation approach is applied to assess the banking system's inherent instability. Moreover, the spill-over effects of a simulated default situation in the interbank market on the liquidity and solvency of banks are measured. The main findings are, first, that there is a substantial potential for contagion. Second, the exposure as well as the credit line contagion channel are relevant for Switzerland. Third, a lender of last resort intervention could reduce spill-over effects remarkably. Finally, the structure of the interbank market has considerable impact on its resilience against spill-over effects: Centralized markets are more prone to contagion than homogenous ones. JEL classification: C81, G21. The opinions expressed herein are my own and not those of the Swiss National Bank.