Other market participants expressed doubts that volatility could be tamped down, as the myriad of measures taken by policymakers to reduce the wild swings in the stock market have been ineffective thus far.
"They tried to encourage long-term investment and also to curb volatility, but I don’t think that can be totally under control at this point," said Tracy Chen, a portfolio manager at Legg Mason unit Brandywine Global in Philadelphia.
"The market’s confidence in Chinese policymakers is a little bit shaky right now."
The CSI300 index comprises the largest listed companies in Shanghai and Shenzhen.
(Reporting by Meg Shen and Twinnie Siu in Hong Kong and Dominique Patton, Meng Meng and Nicholas Heath in Beijing, Chuck Mikolajczak in New York; Editing by Mike Collett-White and Cynthia Osterman)