关键词: 基金共持网络, 小世界性, 无标度性, 演化特征

Abstract: As important institutional investors in the capital market, the behaviour and influence of public funds have always been a hot topic of concern for the industry and academia. In recent years, under the policy of “vigorously developing institutional investors” by the SFC, with the rapid expansion of the number and scale of public funds, in the pursuit of diversified investment, the phenomenon of “inter-fund co-holding”, that is, multiple funds hold one or more stocks together, has become increasingly common and the linkage of holdings among funds has become more networked, with profound implications for investor behaviour, asset pricing and risk management.
However, influenced by the traditional economic thinking, the existing studies on fund co-holding have largely been conducted from the perspective of the impact and economic consequences of institutional shareholding, with most studies treating the shareholding and transactions of different institutions as independent but not considering the interconnectedness of individual institutions. A few studies on investor networks have mostly studied the simple topology (e.g. degree or betweenness centrality, etc.) and characteristics of micro-individual networks from the perspective of directly related networks such as social and business relationships, and their impact on investment decisions and performance, while less attention has been paid to the topological characteristics (especially small-world, scale-free, etc.) and evolutionary patterns of “funds’ co-holding networks” forming indirectly through common holding among funds at the overall network level, as well as what factors influence such overall network characteristics and the underlying fund group behaviour. But these are crucial for understanding information transmission, risk contagion and efficient stock market risk management and investor governance in investor networks. Based on the above,this paper draws on the complex network research methodology to construct the co-shareholding Network between large and small funds(Network 1) and the co-shareholding network between large and small funds(Network 2), and compare their overall topological characteristics and evolutionary features.
The results show that: (1)Although the two networks are large sparse networks, the co-holding behavior among funds still widely exists. (2)Both networks have the characteristics of small-world and scale-free, but there are significant differences in the degree of specificity. (3)There are significant differences in the evolution of “small-world and scale-free of characteristics” between the two networks.
This study provides a reference for understanding the influence of mutual shareholding among funds, and for regulators to manage stock market risk and institutional investor governance.

Key words: funds’ co-holding network, small-world characteristics, scale-free characteristics, evolutionary characteristics