Picture: THINKSTOCK

HONG KONG/BEIJING — Guotai Junan International Holdings plunged 17% in Hong Kong after the brokerage said it was unable to contact its chairman and CEO Yim Fung.

The Hong Kong unit of one of China’s biggest securities firms, Guotai Junan Securities, appointed temporary replacements after failing to reach Mr Yim since November 18, the company told the stock exchange on Monday. The executive "currently cannot discharge his duties", the firm said. Two calls to Mr Yim’s cellphone went to voicemail.

The 17% decline was the biggest intraday fall since July. The shares were down 10.5% as of noon local time.

Based in Hong Kong, Mr Yim is a high-profile figure in the local securities industry, including through his comments to the media and roles with the Chinese Securities Association of Hong Kong. He has been a chairman of the organisation and is now an honorary chairman. In China, he is known as Yan Feng.

The developments at Guotai Junan coincide with a stock market clampdown in China that has seen officials at the securities regulator, senior staff at Citic Securities, and a top fund manager caught up in investigations.

Mr Yim has been a member of the Inner Mongolia arm of the Chinese People’s Political Consultative Conference, a state advisory body.

Mr Yim was named director of the year by the Hong Kong Institute of Directors in 2012 and has been vocal on topics such as the Hong Kong-Shanghai stock link and Qualified Domestic Institutional Investors programme, which allows Chinese investors to access overseas capital markets.

In the crackdown in China, the most senior official to be probed is Yao Gang, a vice-chairman of the China Securities Regulatory Commission. At least 16 have been arrested, are being probed or have been taken away from their job duties to assist mainland authorities. Those probed include Xu Xiang, known as "hedge fund brother No 1" for his knack of timing swings in stocks.

Mr Wong was a bribery probe target by Hong Kong’s Independent Commission Against Corruption in which investigators seized securities trading-account records and an agreement relating to a placement, Guotai Junan International told the stock exchange last December. In June, Guotai Junan International said the probe was over. The commission would not comment.

The Yim announcement is "negative for the brokerage sector", said Andrew Clarke, director of trading at Mirabaud Asia.

Bloomberg