China's securities regulator said on Friday it is investigating an analyst at the country's top brokerage, CITIC Securities Co Ltd , for suspected release of insider information, the latest in its efforts to tighten supervision of illegal trading activities.

State media reported Zhang Mingfang allegedly posted information about Livzon Pharmaceutical Group Inc to a private messaging group, revealing management's equity incentive plans, which subsequently impacted the firm's share price.

The China Securities Regulatory Commission's spokesman Zhang Xiaojun made the announcement at a news briefing on Friday. He did not elaborate.

CITIC Securities, in an email sent to Reuters, said Zhang has been suspended from her post during the investigation.

Attempts to reach Zhang for comment were unsuccessful.

Over the recent past, China has been stepping up its crackdown against illegal trading activities and tightening supervision against fund managers, brokerages, consultants and executives of listed companies in a bid to build confidence in a stock market where illegal trading activities have been rampant.

In 2011, former stock analyst Wang Jianzhong was sentenced to seven years in prison and fined 125 million yuan ($20.13 million), on top of having illicit earnings of the same amount confiscated, becoming China's first convicted stock market manipulator.