We examine how fund ownership and trading contribute to the firm-specific information measured by the stock return synchronicity． Based on hand-collected fund trading data，we find only when the fund ownership of a firm is high，is the fund ownership positively associated with the information contained in the stock price，which reduces the return synchronicity． In addition，we find the fund trading can directly incorporate information into the stock price and lower the stock return synchronicity． Moreover，this negative relationship between fund trading and synchronicity is from the buy-side rather than sell-side． Information transparency of big firms is better，funds’trading on big firms can reveal more firm-specific information，and has a greater impact on synchronicity． Overall，fund ownership and trading behavior can improve the information environment of listed firms and the efficiency of the capital market．