Oil shares soar on news of Zhou's fall from grace

Following the Communist Party of China Central Committee's announcement that former security chief Zhou Yongkang is being investigated on suspicion of "serious disciplinary violations", PetroChina Co Ltd led a rally of oil stocks in morning trading on Wednesday.

Shares in the country's biggest oil and natural-gas producer by output rose 3.33 percent to 8.06 yuan a share at the close of morning trading in Shanghai. Sinopec Ltd, the biggest oil refiner, gained 1.16 percent to 5.23 yuan a share.

Zhou, a former member of the Politburo Standing Committee, China's top decision-making body, started his political career at PetroChina and is widely thought to have acolytes throughout the country's oil industry.

Twenty of the 21 oil-related companies in both the Shanghai and Shenzhen bourses rose, amid a 0.13 percent drop in the benchmark Shanghai Composite Index, ending a six-day rally.