Riyadh has chosen US-based banks JPMorgan Chase and Morgan Stanley along with UK’s HSBC as the lead underwriters for the Aramco’s initial public offering (IPO), billed to be the biggest share sale in the world.

Saudi Aramco has informed the three lenders, which have been the frontrunners to win the mandate, according to Wall Street Journal report which cited unnamed sources. Most of the estimated $100bn proceeds of the public float will be transferred to the kingdom’s sovereign wealth fund Public Investment Fund (PIF), which will invest at home and abroad to diversify the country’s economy.

Officials in January had asked banks to pitch for advisory roles on the IPO. In total six bank were invited to send their proposals, however, a formal announcement on the advisory roles have yet to be made.

Aramco, the world’s top oil exporter, earlier in February selected the investment bank Moelis & Co as an internal independent advisor, as part of a team, tasked with preparing for the share sale. It joins JPMorgan and Michael Klein, an investment banker who runs his own advisory firm, who have already been selected to work on the transaction.

Aramco CEO Amin Nasser said in October that the oil and gas giant will “very soon” announce a list of investment banks and consultants for the IPO. The public offering would cover Aramco’s entire business and not just distribution and refining operations, he said at the time.

Aramco is at the heart of Saudi Arabia’s economic diversification plan, which includes the privatisation of state assets. The measures include reducing subsidies, introducing taxes, spending cuts and increasing and introducing new fees on government services to generate alternative revenue lines.

Aramco has been the main revenue-earner for Saudi Arabia over the past eight decades and it is targeting the second half of the 2018 for the public float. Riyadh aims to list less than 5 per cent of Aramco, which is estimated to be valued at more than $2 trillion.

The primary listing will take place on Saudi Stock Exchange (Tadawul) and one or two as yet unnamed international bourses. It may favour a western exchange including New York, London or Toronto, and is unlikely to pursue listing plans for an Asian exchange despite holding talks with bourses there.

Saudi Aramco IPO timeline

21 February, 2017: Riyadh is likely to list Aramco on a western exchange

9 February, 2017: Aramco appoints IPO advisor

The oil and gas giant has selected a US-based boutique advisory to help prepare for its share sale

24 January, 2017: Saudi Aramco seeks IPO advisers

State-controlled oil and gas giant has asked banks to submit pitches for share sale

17 November, 2016: Saudi Arabia prepares to reveal size of its oil reserves

9 October, 2016: Aramco public offering gathers steam

Indications are Riyadh will fulfil its promise of listing Aramco in its entirety

6 October, 2016: Saudi Aramco prepares to reveal its accounts

The top global oil exporter is getting ready to publish its accounts next year ahead of planned 2018 IPO

27 September, 2016: Aramco is key to Saudi privatisation drive

CEO says listing of “crown jewel’’ shows government’s commitment to economic diversification

 26 September, 2016: Saudi Aramco to spend $334bn over the next decade

Oil well count will increase to 1,000 by 2020,

18 September, 2016: Japan is not eying Aramco IPO investment

The country is interested in jointly investing with the Saudi government in industrial ventures in the kingdom

5 September, 2016: Saudi Aramco may consider listing on Tokyo bourse

The kingdom is preparing to list bout 5 per cent of oil and gas giant on local and international exchanges

28 August, 2016: Aramco IPO is on track for 2018 listing

Saudi Arabia says the process will require time to “optimise’’ value for potential shareholders

11 August, 2016: Aramco appoints investment fund head to its board

Move hints at closer cooperation between PIF and Aramco which are central to kingdom’s economic plans. Yasir al-Rumayyan is the managing director PIF and an advisor to the royal court

30 June, 2016: Saudi Arabia seeks Japanese investment in Aramco IPO

Officials from the two countries are discussing Japan’s investment in Aramco share float, possibly the biggest global IPO

26 April, 2016: Vision 2030: The reforms announced so far

Sweeping overhaul of Saudi economy announced by deputy crown prince including Aramco IPO

25 April, 2016: Riyadh announces sweeping reforms with Vision 2030 plan

Full details of economic roadmap due in 30-45 days

25 April, 2016: Saudi prince reveals economic vision

Deputy Crown Prince Mohammed bin Salman unveils main points of kingdom’s strategy to diversify its economy in next 15 years

25 April, 2016: Saudi Arabia confirms Aramco listing

The kingdom plans to list less than 5 per cent of the company as part of economic reforms

20 April, 2016: Deals galore for investment banks in Saudi Arabia

Saudi Aramco, Tadawul and Saudi Grains are just a few among state entities looking to list shares

20 April, 2016: Saudi Arabia picks Aramco IPO advisors

Riyadh plans to list less than 5 per cent of Aramco’s parent company

3 April, 2016: Saudi Arabia plans $2 trillion sovereign fund

Kingdom to create the world’s largest sovereign wealth fund including the oil giant Saudi Aramco. The Public Investment Fund (PIF), will eventually control more than $2 trillion including ownership of Aramco. Aramco offering could happen in 2018.

20 January, 2016: Spare oil capacity could hinder Aramco’s upstream business listing

The company is more likely to list downstream assets if the government goes ahead with share sale plans

14 January, 2016: Riyadh to maintain controlling stake if Aramco is listed

Oil major’s CEO says a range of options is being considered

11 January, 2016: Aramco listing could include upstream assets

Chairman lists companies slated for stand-alone listings

10 January, 2016: Aramco’s share sale plan is part of a sweeping reform agenda

State oil major’s potential IPO has implications for every energy consumer in Saudi Arabia and practically every energy-importing nation on earth

8 January, 2016: Aramco IPO to accelerate projects market overhaul

Listing is latest new initiative aimed at modernising project delivery in Saudi Arabia

8 January, 2016: Aramco listing could create world’s first $1 trillion company

Timing of IPO suggests government objective is creating wealth not raising funds 

7 January, 2016: Riyadh considers listing Saudi Aramco

State oil company could be worth more than $10 trillion

In an interview with The Economist, Deputy Crown Prince Mohammed bin Salman al-Saud said that a decision will be taken in the next few months and that a listing would make the company more transparent.