Saudi Aramco is eyeing several global cities to launch the world's largest-ever IPO, with New York and London taking the lead.

With plans to publicly float up to five percents of the state-owned oil giant, Riyadh has held talks with Toronto, Singapore, Hong Kong, Tokyo and Shanghai in addition to London and New York. But the UK's capital and the Big Apple appear to be taking the lead.

Some are already suggesting New York will come out on top, but others are saying the race to host the estimated $100 billion public offering is neck-and-neck.

IPO, or initial public offering, is the first time that the stock of a private company is offered to the public.

No final decision has been made

At this point, no decision has been made, individuals familiar with the IPO told the Financial Times.  

But they also said that "London and New York are viewed by Saudi officials, Aramco executives and advisers on the IPO as the only two venues with the breadth of global investors, experience and liquidity to lead an international listing of this size."

In February, the Wall Street Journal reported that New York was the favored candidate.

Some experts think Saudi Aramco is overvalued

A glimpse of Saudi Aramco's oil refinery

Saudi Aramco's $2 trillion estimated value, which would easily consume Apple Inc. twice and Google's parent company Alphabet Inc, may actually be significantly overvalued, according to some experts. 

Speaking to Bloomberg, experts suggested that the company's value is worth "no more than half, and maybe as little as a fifth," of what the kingdom is saying. Their analysis is based on "oil reserves and cash flow projections under different tax scenarios."

Wood Mackenzie Ltd., an Edinburgh-based company, valued the oil giant's core business at just $400 billion. Aramco has declined to comment when pressed about the differing estimates.

If the experts lower valuations are correct, this would mean the IPO would bring significantly less than the $100 billion the kingdom is hoping for. 

But, even if the final amount is lower, the current top IPO of all time was Alibaba Holdings Group's Sept. 18, 2014 launch, which brought in a whopping $21.8 billion. Four days later, the Chinese e-commerce giant sold more shares, bringing the total to $25 billion.

So, even if Saudi Aramco doesn't reach its $100 billion target, it will still have to fall quite far to drop below Alibaba's IPO. 

Why is Saudi Aramco going public?

Low oil prices have hit the Saudi economy hard, forcing the kingdom to cut subsidies and strive to diversify its oil-reliant economy.

Deputy Crown Prince Mohammed bin Salman's ambitious Vision 2030, approved by the Shura Council last June, is making major economic reforms in Saudi Arabia.

Last year, the kingdom announced 20 percent pay cuts for all ministers and 15 percent pay cuts for Shura Council members. Bonuses and other perks were also targeted by the reforms and sales taxes have been introduced. The sale of part of Aramco was also announced with the economic reform plan.

More than two-thirds of Saudis work for the government, with the kingdom spending roughly 45 percent of its budget, or $128 billion, to pay their salaries in 2015.

The kingdom also sold $17.5 billion in debt in October. This was the largest-ever bond sale from an emerging market. The sale was hailed as a major success for the world’s top oil exporter, as it attracted investor interest totaling $67 billion, nearly four times the amount of the sale.

Saudi Arabia's deputy economy minister said that if these economic reforms are not followed, the kingdom faces bankruptcy in three to four years.