Network connections, both across and within markets, are central in countless economic contexts. In recent decades, a large literature has developed and applied flexible methods for measuring network connectedness and its evolution, based on variance decompositions from vector autoregressions (VARs), as in Diebold and Yilmaz (2014). Those VARs are, however, typically identified using full orthogonalization (Sims, 1980), or no orthogonalization (Koop, Pesaran and Potter, 1996; Pesaran and Shin, 1998), which, although useful, are special and extreme cases of a more general framework that we develop in this paper. In particular, we allow network nodes to be connected in ``clusters", such as asset classes, industries, regions, etc., where shocks are orthogonal across clusters (Sims style orthogonalized identification) but correlated within clusters (Koop-Pesaran-Potter-Shin style generalized identification), so that the ordering of network nodes is relevant across clusters but irrelevant within clusters. After developing the clustered connectedness framework, we apply it in a detailed empirical exploration of sixteen country equity markets spanning three global regions.
翻译:网络连接,无论是跨市场还是市场内部,在众多经济情境中均处于核心地位。近几十年来,基于向量自回归(VAR)模型的方差分解方法,如Diebold和Yilmaz(2014)的研究,已发展并广泛应用了多种灵活测量网络连通性及其演变的工具。然而,这些VAR模型通常采用完全正交化(Sims, 1980)或无正交化(Koop, Pesaran和Potter, 1996; Pesaran和Shin, 1998)进行识别,这些方法虽具实用性,但属于本文所构建的更一般框架中的特殊及极端情况。具体而言,我们允许网络节点以“聚类”形式连接,例如资产类别、行业、区域等,其中冲击在聚类间正交(Sims风格的正交化识别),但在聚类内相关(Koop-Pesaran-Potter-Shin风格的广义识别),从而使网络节点的排序在聚类间具有相关性,而在聚类内无关。在建立聚类连通性框架后,我们将其应用于对跨越全球三个区域的十六个国家股票市场的详细实证分析中。