Citadel, a U.S.-based hedge fund, confirmed that trading in one of the accounts it manages in China has been restricted by China's securities regulator, a company representative said on Monday.
"Citadel has been actively investing in the region for 15 years, and has always maintained a constructive dialogue with regulators, including during the recent market volatility," a company statement said.
"We can confirm that while one account managed by Guosen Futures - Citadel (Shanghai) - has had its trading on the Shenzhen Exchange suspended, we continue to otherwise operate normally from our offices, and we continue to comply with all local laws and regulations."
China's securities regulator has restricted trading in 34 stock accounts for suspected trading irregularities, including abnormal bids for shares and bid cancellations that might have impacted wider market performance.
The regulator indicated it was particularly concerned over automated trading strategies.
The Chinese government has intervened massively on multiple fronts to rescue its stock market after it slumped more than 30 percent in less than four weeks following June 12. But it has struggled to produce a sustainable turnaround so far.