The head of the Shenzhen Energy Group is under official investigation, according to sources in the mainland power and securities sectors.
Lao Derong is believed to be the second mainland power sector official to face a probe in the final weeks leading up to a top leadership reshuffle at next month's 16th Communist Party Congress and the imminent announcement of senior personnel changes in the national power industry overhaul.
News of Ms Lao's apparent fall from grace comes on the heels of last month's disappearance of State Power Corp president Gao Yan.
Mr Gao, formerly at the helm of China's biggest energy firm and the lame-duck power sector regulator, is widely believed to be under investigation.
Both events are being seen by some as signs of score-settling by feuding factions within China's communist hierarchy as they jostle for power ahead of the party congress beginning on November 8.
Beijing had been expected to finalise within days changes in the top level of the mainland's power sector leadership, a mainland industry executive said, although a public announcement was not anticipated until next month.
