Abstract: It is of great significance to examine whether fund managers have independence in the stock selection and can make contributions to identifying and delivering firm-specific information to improve market efficiency relying on their professional skills. To find the effect of network contagion on stock pricing efficiency, the open-end fund quarterly data with the period of 2006-2018 are chosen as samples, building a new kind of fund investment relationship network which calls "a multi-valued signed network based on similarity in fund position changing" and the relationship between clustering coefficient and stock price is examined synchronicity. At the same time, it was also verified whether there is a difference in the relationship between network contagion and stock-cum-synchronization under the conditions of different fund shareholding ratio, different market situation, and different analysts' attention. The results indicate that fund managers in China have strong imitation relationships on bulk-holding stocks selection and stable structures of similarity network. No private information or industry information sharing in the network, the network contagion reduces the pricing efficiency in the stock market and it was "intentional herding". This paper has both theoretical and practical significance on how to effectively identify the herd behavior of fund managers and prevent related risks.

Key words: open-ended funds, funds position changing, network contagion, clustering coefficient, stock price synchronicity