EPJ Data Sci. (2016) 5: 10
https://doi.org/10.1140/epjds/s13688-016-0071-7

Regular article

Backbone of credit relationships in the Japanese credit market

¹ Dipartimento di Fisica e Chimica, Universitá degli Studi di Palermo, Viale delle Scienze, Ed. 18, Palermo, I-90128, Italy
² Graduate School of Simulation Studies, The University of Hyogo, Kobe, 650-0047, Japan
³ Department of Mathematics, Niigata University, Niigata, 950-2181, Japan
⁴ Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
⁵ Dipartimento di Scienze Economiche e Sociali, Università Politecnica delle Marche, Piazza Martelli, 8, Ancona, 60121, Italy
⁶ Center for Network Science and Department of Economics, Central European University, Nador 9, Budapest, 1051, Hungary

^* e-mail: rn.mantegna@gmail.com

Received: 15 November 2015
Accepted: 9 March 2016
Published online: 22 March 2016

Abstract

We detect the backbone of the weighted bipartite network of the Japanese credit market relationships. The backbone is detected by adapting a general method used in the investigation of weighted networks. With this approach we detect a backbone that is statistically validated against a null hypothesis of uniform diversification of loans for banks and firms. Our investigation is done year by year and it covers more than thirty years during the period from 1980 to 2011. We relate some of our findings with economic events that have characterized the Japanese credit market during the last years. The study of the time evolution of the backbone allows us to detect changes occurred in network size, fraction of credit explained, and attributes characterizing the banks and the firms present in the backbone.