Li Xueming, vice-chairman of China Everbright International Ltd, resigned from his post, a move that drove its shares more than 8 percent higher on Thursday.
The Hong Kong-listed company is a division of a State-owned Chinese conglomerate.
Shares in the company ended up 8.18 percent at HK$3.57 (46 cents) on news of the resignation, outpacing a 0.8 percent gain in the benchmark Hong Kong index.
The company said in a statement on Wednesday that Li had decided to resign from the board for the best interests of the company and its shareholders as a whole in order to "minimize any possible adverse impact on the company of some recent media coverage on his family background".
The statement did not specify what Li's family background is, but according to media reports, Li is the brother of Bo Xilai, the former Party chief of Chongqing, who was suspended by the Central Committee of the Communist Party of China and is under investigation on suspicion of serious breaches of discipline.
China Everbright International Ltd is an alternative energy company focusing on research, development and operation of energy-saving products and new energy sources.
Li was appointed as executive director and vice-president of the board in June 2003, according to the Guangzhou-based Time Weekly.
The 64-year-old Li sold 12 million shares in China Everbright in 2010 and 2011, cashing out HK$43.2 million, which left Li with 10 million options (about 0.27 percent), according to the company's latest annual report, Bloomberg News reported on Thursday.
Li's annual salary from the company was HK$1.7 million in 2011, according to Bloomberg.
The company's statement said Li's dedication and diligence in serving the company during his tenure of directorship and his contributions to the company were recognized and appreciated.
"Recent reports by the media on Mr Li's family background have no relationship with the normal business and operations of the company, and have not affected and will not affect the normal business and operations of the company and its subsidiaries," it said.
The business of the company and its subsidiaries are currently operating normally with excellent prospects of future development, the statement said.