Saudi Aramco, the world’s top oil exporter, has appointed Yasir al-Rumayyan, the managing director of Public Investment Fund (PIF) and an advisor to the royal court, to its board, according to the company’s website.

The move signifies closer cooperation between the two institutions going forward, which are at the heart of kingdom’s economic diversification plan amid shrinking revenues on the back of lower oil prices.

The state-owned Aramco updated website now includes Al-Rumayyan in the list of board members but it doesn’t say who he has replaced. News agency Reuters said Rumayyan has replaced telecommunications minister Mohammed al-Suwaiyal on the board.

Saudi Aramco is the kingdom’s biggest company and has been its main revenue earner for more than eight decades. It is at the centre of government plans to wean its economy off oil by 2020. Proceeds from sale of hydrocarbons currently accounts for more than 80 per cent of the country revenues. Slide in oil prices from the mid-2014 of more than $110 per barrel to current close to $45 per barrel means the kingdom this year is facing a budget deficit of about $87bn.

Saudi Arabia in January said that it will list less than 5 per cent of the Saudi Aramco’s shares on Saudi Stock Exchange and an international bourse. The ownership of the rest of Aramco will be transferred to PIF, which will inflate its size to estimated $2trillion.

Al-Rumayyan is spearheading the transformation of PIF, which will invest on behalf of the government at home and abroad to diversify its revenue streams and develop its non-oil sector.

Officials have been studying proposals for an Aramco share offer for months, however concrete plans have yet to emerge. The government is considering several options as the sheer size of the public float makes it difficult to list it on the local bourse.