Oil giant Saudi Aramco on Sunday kicked off a secondary share offering that could fetch nearly $12 billion, bolstering state finances amid ambitious economic reforms.

The firm last Thursday disclosed plans to sell 1.545 billion shares on the Saudi stock market, priced between 26.70 and 29 Saudi riyals ($7 to $7.70).

Sunday marked the beginning of the book-building period for investors inside and outside the kingdom, Aramco said in a statement, allowing officials to gauge demand.

Meetings with institutional investors were set to run through Thursday while about 10 percent of the shares would be offered to retail investors from Monday, the statement said.

The final offer price will be announced on Friday and the shares will begin trading on Sunday, it said.

It is the firm's second listing after an initial public offering in December 2019 that raised $25.6 billion, the biggest flotation in history.

Saudi Arabia is the world's largest crude oil exporter and currently owns 82.18 percent of Aramco's shares, though that amount will fall to around 81.5 percent after the second share sale, Sunday's statement said.

Crown Prince Mohammed bin Salman, Saudi Arabia's de facto ruler, is depending on Aramco's profits to finance a sweeping economic and social reform programme known as Vision 2030, which aims to lay the groundwork for an eventual post-oil future.

Flagship projects include NEOM, the futuristic mega-city being built in the desert at a cost of at least $500 billion, a giant airport in Riyadh and major tourism and leisure developments.

In 2022 Prince Mohammed announced the transfer of a four-percent chunk of Aramco shares, estimated to be worth around $80 billion, to the kingdom's sovereign wealth fund, the Public Investment Fund.

Last year, the kingdom announced the transfer of a second four-percent portion of shares to Sanabil Investments, a firm controlled by the PIF.

And in March, Riyadh said an additional eight percent Aramco stake had been transferred to firms owned by the PIF, which with its subsidiaries now controls 16 percent of the company.