An audit of Saudi Aramco’s oil reserves has found the state oil giant’s reserves to be higher than previously reported.

According to a media report, an independent external audit has found the proven oil reserves to be at least 270 billion barrels, which is higher than the 260.8 billion barrels the company reported in its 2016 annual review.

Saudi Arabia’s reserves of conventional oil have long been the world’s largest.

Aramco’s official reserves figures were “more than confirmed” Reuters quoted a source as saying. “This is good for the company’s valuation,” another source said.

US-based DeGolyer & MacNaughton and Gaffney, Cline & Associates, part of Baker Hughes, are involved in the auditing, Reuters said.

Having an internationally recognised reserves audit has become a key task for Aramco as it seeks to become the world’s most valuable company when it lists a 5 per cent stake through an initial public offering (IPO) later this year or early 2019.

Aramco claims to be worth $2 trillion, a value that is based on data kept confidential by the energy behemoth. Higher oil reserves and favourable oil prices are crucial to Aramco attaining the desired valuation and raising $100bn from its stock listing.

For nearly three decades – despite rising production, large swings in oil prices and improved technology – Riyadh has annually reported the same number for reserves at about 261 billion barrels, according to BP’s statistical review.