A Network Analysis Of Global Banking

In this paper we explore the properties of the global banking network using cross-border bank lending data for 184 countries over 1978-2009. Specifically, we analyze financial interconnectedness using network metrics of centrality, connectivity, and clustering. We document a relatively unstable global banking network, with structural breaks in network indicators identifying several waves of capital flows. Interconnectedness rankings, especially for borrowers, are relatively volatile over the period. Connectivity tends to fall during and after systemic banking crises and sovereign debt crises. The 2008-09 global financial crisis stands out as an unusually large perturbation to the cross-border banking network.

The 2008/9 financial crisis highlighted the importance of evaluating vulnerabilities owing to interconnectedness, or Too-Connected-to-Fail risk, among financial institutions for country monitoring, financial surveillance, investment analysis and risk management purposes. This paper illustrates the use of balance sheet-based network analysis to evaluate interconnectedness risk, under extreme adverse scenarios, in banking systems in mature and emerging market countries, and between individual banks in Chile, an advanced emerging market economy.

This paper applies network analysis to assess the extent of systemic vulnerabilities in the ECCU banking system. It includes two sets of illustrative stress tests. First, solvency and liquidity shocks to each individual bank and the impact on other banks in the network through their biltareal net asset exposures. Second, country and region-wide tail shocks to GDP affecting capital and liquidity of all banks in the shocked jurisdictions, followed by the rippling effects through the regional network. The results identify systemic institutions that merit hightened attention by the regulator, as determined by the degree of connectivity with the rest of the system, and the extent to which they are vulnerable to the failure of other banks.

Post-crisis dynamics show a shrinkage in the overall amount of crossborder bank lending, which has been interpreted in the literature as a retreat in financial globalization. In this paper, we argue that aggregate figures are not sufficient to support such a claim in terms of the overall structure of the global banking network. Based on a systematic approach to measuring, mapping and analyzing financial interconnectedness among countries using network theory, we show that, despite the decline in aggregate lending volumes, the structure of the network has developed increased connections in some dimensions. Some parts of the network are currently more interlinked regionally than before the crisis, and less dependent on major global lenders. In this context, at a more disaggregate level, we document the characteristics of the increasing regionalization of lending flows, the different evolution of linkages through bank affiliates and direct cross-border claims, as well as the shift in the importance of key borrower and lender nodes. These changes in the banking network have important insights in terms of policy implications since they indicate that the global banking network has evolved, but it has not undergone a generalized retrenchment in financial linkages.

Shortly after the financial crisis of 2007-2008 many authors began to write about certain “huge institutions” potentially able to damage the entire financial system through negative shocks, approaching the issue of systemic risk in banking through the evaluation of the so called “Too-Big-to-Fail” actors. While the size of a bank is certainly a factor of risk when considering systemic implications, this book also explores the properties of some deeply interconnected institutions. The author’s main intuition is based on the renowned work by Mark Granovetter on “The Strength of Weak Ties” and “Economic Action and Social Structure: The Problem of Embeddedness”: dangerous flows, like financial shocks, may travel very quickly through networks in unexpectedly efficient ways thanks to “Weak Ties”. The existence of weaker yet longer ties implies a naturally “robust yet fragile” network where even distant actors are closely interconnected, sharing both opportunities and risks. As a consequence, some nodes may act as key actors under the structural perspective. It is therefore critical for the central authority to identify and closely monitor said institutions. Thanks to a journey through the history of Social Network Analysis this book offers a complete overview on the evolution of the methodology and the most recent applications to systemic risk assessment, which are completed by a critical approach towards the “Too-Interconnected-to-Fail” perspective.

This paper applies network analysis to assess the extent of systemic vulnerabilities in the ECCU banking system. It includes two sets of illustrative stress tests. First, solvency and liquidity shocks to each individual bank and the impact on other banks in the network through their biltareal net asset exposures. Second, country and region-wide tail shocks to GDP affecting capital and liquidity of all banks in the shocked jurisdictions, followed by the rippling effects through the regional network. The results identify systemic institutions that merit hightened attention by the regulator, as determined by the degree of connectivity with the rest of the system, and the extent to which they are vulnerable to the failure of other banks.

Post-crisis dynamics show a shrinkage in the overall amount of crossborder bank lending, which has been interpreted in the literature as a retreat in financial globalization. In this paper, we argue that aggregate figures are not sufficient to support such a claim in terms of the overall structure of the global banking network. Based on a systematic approach to measuring, mapping and analyzing financial interconnectedness among countries using network theory, we show that, despite the decline in aggregate lending volumes, the structure of the network has developed increased connections in some dimensions. Some parts of the network are currently more interlinked regionally than before the crisis, and less dependent on major global lenders. In this context, at a more disaggregate level, we document the characteristics of the increasing regionalization of lending flows, the different evolution of linkages through bank affiliates and direct cross-border claims, as well as the shift in the importance of key borrower and lender nodes. These changes in the banking network have important insights in terms of policy implications since they indicate that the global banking network has evolved, but it has not undergone a generalized retrenchment in financial linkages.

The contributions in this volume cover a broad range of topics including maximum cliques, graph coloring, data mining, brain networks, Steiner forest, logistic and supply chain networks. Network algorithms and their applications to market graphs, manufacturing problems, internet networks and social networks are highlighted. The "Fourth International Conference in Network Analysis," held at the Higher School of Economics, Nizhny Novgorod in May 2014, initiated joint research between scientists, engineers and researchers from academia, industry and government; the major results of conference participants have been reviewed and collected in this Work. Researchers and students in mathematics, economics, statistics, computer science and engineering will find this collection a valuable resource filled with the latest research in network analysis.