China’s central government is being urged to investigate possible illegal transfers of shares in the privatisation of one of the country’s biggest power companies in a case that could have significant political fallout.

Control of the Luneng Group, in Shangdong province, was acquired by two Beijing-based private companies for Rmb3.73bn ($480m, €370m, £244m) last year after a complicated restructuring in which shares were issued to employees and bought back by the new owners.