PetroChina, China’s largest oil and gas group, has chosen UBS to help raise up to $6bn in what is poised to be one of the biggest listings on the country’s mainland market.

PetroChina is the latest big state-owned company to decide to seek a Shanghai listing, underlining Beijing’s efforts to damp investor exuberance by increasing the supply of new shares coming on to the market. The Shanghai composite index closed down 2.36 per cent at 3,821.92 on Monday, having risen more than 40 per cent this year.