Saudi Arabia’s small stock exchange is scrambling to prepare for the world’s biggest initial public offering: shares in the country’s oil driller Aramco.

The total value of the Tadawul, as the Saudi stock exchange is named, is about $500 billion among 191 companies. By comparison, the market value for iPhone maker Apple is about $877 billion, and the total value of shares traded on the New York Stock Exchange was more than $20 trillion as of last year.

The Tadawul may get overwhelmed by the IPO for a minority stake in Aramco, which Saudi Arabia estimates has a total value of $2 trillion, The Wall Street Journal reported.

“I don’t think the Saudi local market can float a $100 billion IPO,” Babatunde Ojo, an analyst and frontier- and emerging-markets portfolio manager at Harding Loevner, told the Journal. The kingdom has said it hopes to raise that amount in the sale of Aramco shares to investors.

The Tadawul and its regulators have worked on changes designed to bring its technology in line with international standards and to bring in more overseas investors. The bourse was closed to foreign investors until 2015, and has registered 130 international financial institutions since then.

Aramco’s listing on the Tadawul will make the exchange more depend on movements in oil prices, even as Saudi Crown Prince Mohammed bin Salman seeks to make his country’s economy less dependent on one industry. Energy stocks make up a tiny slice of Saudi Arabia’s stock market, accounting for just 2.3 percent of value traded on the Tadawul.

When the Aramco listing was first announced in 2016, Prince Mohammed told advisers he was most interested in floating it on the New York Stock Exchange, sources familiar with the potential listing told the Journal.

Potential legal and regulatory hurdles of an international Aramco IPO have become more complicated than initially expected, leading kingdom officials to look more carefully at a domestic-only listing.

The timeline for the IPO is still uncertain, but Saudi Arabia wants oil prices to rise to $80 a barrel to support a strong valuation for Aramco, Time magazine reported. London’s benchmark Brent crude futures trade for $70.21 a barrel.

"We believe oil prices will get higher in this year and also get higher in 2019, so we are trying to pick the right time," Prince Mohammed told the magazine in reference to the IPO.

• Saudi Arabia Is Said to Signal Ambition for $80 Oil Price
• CalSTRS CIO Joins #DeleteFacebook Movement, Axing His Page