Beyond Connectivity: Stock Market Participation in a Network

Abstract

What are the aggregate and distributional consequences of the relationship between an individual’s social network and financial decisions? Motivated by several well-documented facts about the influence of social connections on financial decisions, we build and calibrate a model of stock market participation with a social network that emphasizes the interplay between connectivity and network structure. Since connections to informed agents help spreading information, there is a pivotal role for homophily. An increase in the average number of connections raises the average participation rate, mostly due to richer agents. Higher homophily benefits richer agents by creating clusters where information spreads more efficiently. We show empirical evidence consistent with the importance of connectivity and sorting. We discuss several new avenues for future research into the aggregate impact of peer effects in finance.

Keywords: Social Networks, Peer Effects, Stock Market Participation, Connectivity, Homophily