Preparations for the world's largest IPO (initial public offering) of Saudi's national petroleum and natural gas company, Aramco, are underway after it got delayed last year as the company acquired a $69 billion stake in a state chemical maker.

The IPO process went to full gear again when Aramco finished a $12 billion bond sale just this April.

Not only is Saudi Aramco one of the largest companies in the world, but Bloomberg also credits it as the most profitable.

As the company prepares for its IPO, Energy Minister Khalid Al-Falih had been replaced, from being Chairman of Saudi Aramco, by Yasir Al-Rumayyan, the current head of the sovereign wealth fund.

Mr. Al-Falih had held his position in Aramco since 2015.

Through a tweet, Mr. Falih wished Mr. Rumayyan success in his new role and added that the new appointment is needed for the company's preparation for an IPO.

People privy to Mr. Falih's real stand on Aramco's IPO told Financial Times that he had warned of the negative exposure a listing could bring and the uncertainties of the times because of the ongoing global economic issues.

Mr. Rumayyan, Aramco's new chairman, is not only an Aramco board member but also a key adviser to Crown Prince Mohammed Bin Salman.

He gained influence as head of the country's Public Investment Fund. This is where Prince Mohammed wants to diversify the kingdom's economy too.

Aramco's chairmanship had always been held by the energy minister because the government is in charge of production policy and managing reserves.

Unlike past chairmen who had vast experience in the kingdom's energy industry, Mr. Rumayyan is a former banker and regulator.

He had been an adviser to the royal court since 2015 and became influential when King Salman sat on the throne and handed the transformation of Saudi's economy to his son, Prince Mohammed.

The Public Investment Fund is helping Prince Mohammed with the fundings for his domestic reforms coupled with international investments that include Japan's SoftBank's Vision Fund, US ride-hailing Uber and US electric carmaker Tesla.

The replacement was strategically made to separate the Ministry of Energy from Aramco to avoid any issues as the state-owned company prepares for its IPO.

The kingdom's de facto ruler, the Crown Prince, puts Aramco over $2 trillion. Analysts put it at $1.5 trillion.

International banks had started vying for a role for Aramco's IPO since last week.

Considering this "a big signature initiative of Crown Prince Mohammed" is Helima Croft, chief commodities strategist at the global investment bank RBC Capital Markets.

She also confirmed the noticeable acceleration of "the IPO timeline."

Though there is no definite time yet, Saudi officials would like to go ahead with the initial public offering by 2020 or 2021.