As illustrated by the 2008 global financial crisis, the financial distress of one country can trigger financial distress in other countries. We examine the problem of identifying such “systemically important” countries (i.e., countries whose financial distress can trigger further distress), which is important for assessing global financial stability. Using data on bilateral financial positions that are split by asset type, we build a multiplex global financial network in which nodes represent countries, edges encode cross-country financial assets of various types, and layers represent asset types. We examine the temporal evolution of a measure of node importance known as MultiRank centrality, and we find that several major European countries decrease in rank and that several major Asian countries increase in rank since 2008. We then develop a multiplex threshold model of financial contagions in which a shock can propagate either within a layer or between layers. We find that the number of systemically important countries can be twice as large when we take into account the heterogeneity of financial exposures (i.e., when using a multiplex network) than in a contagion on an associated aggregate global financial network (i.e., on a monolayer network), as is often examined in other studies. We also study the extent to which buffers can reduce the propagation of financial distress. Our analysis suggests that accounting for both intralayer and interlayer propagation of contagions in a multiplex structure of financial assets is important for understanding interconnected financial systems of countries.

正如2008年全球金融危机所显示的，一个国家的财务困境可能会引发其他国家的财务困境。我们研究了识别此类“具有系统重要性”的国家（即财务困境可能引发进一步困境的国家）的问题，这对于评估全球金融稳定至关重要。利用按资产类型划分的双边金融头寸数据，我们构建了一个多元化的全球金融网络，其中节点代表国家，边编码各种类型的跨国金融资产，层次代表资产类型。我们研究了一种称为MultiRank中心度的节点重要性度量的时间演变，发现自2008年以来，几个主要的欧洲国家/地区排名下降，几个主要的亚洲国家/地区排名上升。然后，我们建立金融传染的多重阈值模型，其中冲击可以在层内或层之间传播。我们发现，考虑到金融风险的异质性（即使用多重网络时），具有系统重要性的国家的数量可以是相关联的全球金融网络（即单层）上的传染性的两倍。网络），这在其他研究中经常被检查。我们还研究了缓冲措施在多大程度上可以减轻财务困境的蔓延。我们的分析表明，在金融资产的多重结构中，应对传染物在层内和层间传播的会计处理对于理解国家相互联系的金融系统非常重要。