With the wild swings in the country's stock market showing no signs of abating, Beijing's attempt to put a lid on volatility has been ratcheted up a notch, with a senior official at the securities regulator tasked with propping up the stock market being placed under investigation on Wednesday.  Zhang Yujun, the assistant chairman of the China Securities Regulatory Commission (CSRC), is being probed for "severe violation of discipline," according to a statement by the Central Commission for Discipline Inspection late Wednesday.  The online statement by the anti-graft watchdog did not provide further details but according to Reuters, disciplinary violations are often used as a euphemism for corruption.  Zhang, 53, is the first senior official from the securities regulator to be entangled in a government investigation over the country's stock market meltdown. According to his profile page on the CSRC website, he is one of the regulator's three assistant chairmen and previously served as general manager at the Shanghai and Shenzhen stock exchanges.  Read MoreWhat's with China's mixed policy messages?  Is this part of a broader trend?  Since the painful selloff unfolded in mid-June, Beijing has rolled out an unprecedented slew of policies to curb what authorities call "malicious" trading. Measures include a freeze on initial public offerings, direct share purchases by state entities, considerations of a market-wide 'circuit breaker' mechanism and the drafting of new rules for commodity exchanges.  In recent months, authorities have intensified its market probe on alleged market manipulation, issuing penalties to stock trading platforms, as well as netting journalists and social media users.  The scrutiny on CSRC's Zhang comes on the back of investigations on the president and two other executives from Citic Securities for insider trading and leaking information. China's largest brokerage house has been in the spotlight since four senior executives from Citic confessed to insider dealing in August, according to state media reports.  The People's Bank of China (PBOC) also lowered interest rates and reserve requirement ratios in a bid to bolster sentiment. Still, indexes in Shanghai and Shenzhen continued to succumb to heavy selling pressure, losing over 40 percent since their peaks on June 12.  The anti-graft watchdog on Thursday also urged China's banking regulators to step up on vigilance and "ensure no stone is left unturned" while eliminating illegal activities.  "Handle in accordance with the rules problems of breaches of discipline and the law," a Reuters report cited the Central Commission for Discipline Inspection as saying. "Ensure no stone is left unturned."
Chinese authorities have targeted a senior official at the country's securities regulator for the first time since market volatility took off.