The Philippines on Monday cleared Ashmore, the emerging markets investment fund, to buy Saudi Aramco’s 40 per cent stake in Petron Corp, the country’s biggest petrol refiner, for $550m.

The state-owned Philippine National Oil Company owns another 40 per cent of Petron and had a pre-emptive right to buy Saudi Aramco’s shares or assign that option to a third party. PNOC directors on Monday decided not to exercise the option.