TDG Holding (SHA:600330) said three of its controllers reduced part of their company shares, according to a Shanghai bourse filing on Saturday.

The electronic materials manufacturer's shares slumped 8% at the close of Monday's trade.

Pan Jianzhong, Pan Juanmei and Yu Zhihua collectively offloaded 1.56%, or 19,234,083 shares in the company. After the transaction, the combined holdings of all actual controllers and persons acting in concert declined to 17.34% from 18.90%.