Abstract: Based on the market reaction to share repurchase plans of listed companies in China, this paper investigates whether the new share repurchase regulation of 2018 (hereafter, SRR-2018) improves investors' interest protection. We find that, during the post-SRR- 2018 period, there were more announcements of share repurchase plans, and these plans also had positive market reactions; however, the market reactions were significantly weaker than before, and this phenomenon was more pronounced for the share repurchase plans with the market value management motive, the companies with lower ratios of cash holdings to the upper limits of share repurchase funds, those with lockup expiration of non-tradable shares in the next six months, and those with large shareholders' share pledging. On the oth- er hand, the market reactions to the announcements of the first actual repurchases during the post-SRR-2018 period were more positive than before. Furthermore, the long-term stock returns that accompanied the repurchase plans were lower, and the net insider selling was more. Hence, the SRR-2018 may have fallen short of the regulator's expectations and actually do harm to investors' interests.

Key words: the new share repurchase regulation of 2018, investor protection, market reaction