Abstract: Can institutional investors improve the transparency of corporate information disclosure and restrain the private-interest behaviors of the controlling shareholders by forming institutional investor groups through social network connection? This is a topic worth indepth study. Taking A-share listed companies from 2016 to 2020 as the research samples, this paper identifies the shareholding of institutional investors groups from the network of institutional investors based on social network algorithm, then it studies the influence of the shareholding of institutional groups on the information quality of critical audit matters (CAMs). The findings show that the shareholding of institutional investor groups has significantly improved the information quality of CAMs, which is manifested as that the higher proportion of shares of the enterprises held by institutional investor groups, the more diversified the disclosure forms of CAMs, the more sufficient the disclosed content, the lower the text similarity, and the higher the readability of the text. The results of the mechanism study show that the shareholding of institutional investor groups can realize the improvement of the information quality of CAMs mainly through the information supervision effect. The cross sectional analysis reveals that the information quality of CAMs is higher in the groups without institutional investor visits or with shareholdings of the long-term institutional investor groups. The above conclusions imply that in order to improve the information quality of CAMs, the auditors should have a macro-perspective of auditing the whole situation, the institutional investor groups should establish long-term value investment awareness and hold core investment concepts, and the supervision agencies should quicken the mechanism construction for the long-term institutional investors to participate in the markets .

Key words: institutional investor groups, critical audit matters, social network, information quality