Saudi Arabia could include at least part of its crude reserves in the potential sale of shares in state-owned oil producer Saudi Aramco, according to the company’s chairman.

Khalid al-Falih said in an interview with the Wall Street Journal that studies on the potential initial public offering (IPO) are still ongoing.

“We are considering a listing at the top. So a listing of the main company, and obviously the main company will include upstream,” Al-Falih told the newspaper, adding that Aramco is also looking into listing refining and petrochemicals assets.

Many of Aramco’s downstream assets are joint ventures with international oil companies (IOCs) and petrochemicals companies, which would make the listing more complex.

Al-Falih said that firms already being looked at for stand-alone listings include Sadara Chemical Company, Saudi Aramco Total Refining and Petrochemical Company (Satorp) and Yanbu Aramco Sinopec Refining Company (Yasref).

The potential public listing of Aramco shares was revealed by Deputy Crown Prince Mohammed bin Salman in an interview with The Economist published on 7 January.

Capital Economics estimates Aramco could be worth anything from $1 trillion to upwards of $10 trillion.

Aramco is looking at listing shares primarily on the Saudi Stock Exchange (Tadawul) “but I would not exclude at this stage international listings given the potential size”, Al-Falih said.