OREANDA-NEWS. September 17, 2013. China oil construction company Wison Engineering Services Co Ltd said its controlling shareholder Hua Bangsong "is assisting relevant authorities" in China who are conducting an investigation after sharp falls in Wison's share price.

Wison, which counts PetroChina among its major customers, did not elaborate on the investigation. It said it issued the statement after Chinese media reports about its business relationships with PetroChina.

Hua was not immediately available for comment.

Beijing said on Sunday it was investigating the head of its state assets regulator, a former chairman of PetroChina, for "serious discipline violations" in what appears to be a deepening crackdown on corruption and a push for reform.