eprintid: 1115
rev_number: 8
eprint_status: archive
userid: 6
dir: disk0/00/00/11/15
datestamp: 2012-02-13 14:54:52
lastmod: 2018-03-08 17:07:48
status_changed: 2012-02-13 14:54:52
type: article
metadata_visibility: show
creators_name: Garlaschelli, Diego
creators_name: Battiston, Stefano 
creators_name: Castri, Maurizio
creators_name: Servedio, Vito D. P.
creators_name: Caldarelli, Guido
creators_id: diego.garlaschelli@imtlucca.it
creators_id: 
creators_id: 
creators_id: 
creators_id: guido.caldarelli@imtlucca.it
title: The scale-free topology of market investments
ispublished: pub
subjects: HB
subjects: HG
divisions: EIC
full_text_status: none
keywords: PACS:89.75.-k; 89.65.Gh; 02.50.Ey; 87.23.Ge. Keywords:     Complex networks; Econophysics; Wealth distribution;     Pareto's law
abstract: We propose a network description of large market investments, where both stocks and shareholders are represented as vertices connected by weighted links corresponding to shareholdings. In this framework, the in-degree (kin) and the sum of incoming link weights (v) of an investor correspond to the number of assets held (portfolio diversification) and to the invested wealth (portfolio volume), respectively. An empirical analysis of three different real markets reveals that the distributions of both kin and v display power-law tails with exponents γ and α. Moreover, we find that kinscales as a power-law function of v with an exponent β. Remarkably, despite the values of α, β and γ differ across the three markets, they are always governed by the scaling relation β=(1-α)/(1-γ). We show that these empirical findings can be reproduced by a recent model relating the emergence of scale-free networks to an underlying Paretian distribution of ‘hidden’ vertex properties.
date: 2005
publication: Physica A: Statistical Mechanics and its Applications
volume: 350
number: 2-4
publisher: Elsevier
pagerange: 491-499
id_number: 10.1016/j.physa.2004.11.040
refereed: TRUE
issn: 0378-4371
official_url: http://dx.doi.org/10.1016/j.physa.2004.11.040
related_url_url: http://arxiv.org/abs/cond-mat/0310503
citation:   Garlaschelli, Diego and Battiston, Stefano  and Castri, Maurizio and Servedio, Vito D. P. and Caldarelli, Guido  The scale-free topology of market investments.  Physica A: Statistical Mechanics and its Applications, 350 (2-4).  pp. 491-499.  ISSN 0378-4371      (2005)