RIYADH/DUBAI (Reuters) – Saudi Aramco has agreed to buy a 70 percent stake in Saudi Basic Industries Corp (SABIC) from Saudi Arabia’s sovereign wealth fund for $69.1 billion, in a deal which the world’s top oil producer called “historic.”

SABIC and Aramco said in a statement the agreed purchase price is 123.39 riyals per share, a slight discount from SABIC’s closing price on Wednesday.

“This is a win-win-win transaction and a transformational deal for three of Saudi Arabia’s most important economic entities,” said Yasir Othman Al-Rumayyan, managing director of the Public Investment Fund (PIF).

The deal comes after months of talks between Aramco and PIF, which contributed to the delay of Aramco’s planned multi-billion dollar initial public offering.

Aramco has been boosting its investments in refining and petrochemicals to secure new markets for its crude, as it sees growth in chemicals as central to its downstream expansion strategy.

Aramco’s CEO Amin Nasser said the deal represented an “historic moment” and a “great opportunity for growth,” Saudi-owned broadcaster Al Arabiya reported.

“Solidifying our relationship in this way strategically positions SABIC and Saudi Aramco to accelerate exciting developments in our global chemicals business,” said Yousef Al-Benyan, SABIC Vice Chairman and CEO.

Aramco said it has no plan to buy the remaining shares in SABIC, the world’s fourth-biggest petrochemicals firm.

Aramco plans to increase its refining capacity from 4.9 million to 8-10 million barrels per day by 2030.

“We think that Aramco will now run all of its future expansion plans directly through SABIC, and with a big part of the 2030 vision focused on expanding petchems, this only bolsters SABIC’s long term growth potential,” said Yousef Husseini, an analyst at EFG-Hermes.

Saudi Aramco and SABIC have petrochemicals production capacity of 17 and 62 million tons per year, respectively.

“While we don’t expect Aramco to treat the investment quite as passively as the PIF did, we also don’t expect them to interfere in the day to day of SABIC, especially since both companies’ strategies seem aligned at this point and focused on international growth,” Husseini said.