Berkshire Hathaway, the Warren Buffett-owned conglomerate, hasannounced its biggest deal inthree years with the planned acquisition of OxyChem for $9.7 billion.

This will be Buffett’s biggest deal since he paid $11.6 billion for Alleghany, an insurance company, in 2022. Buffett, 95,recently announced he was stepping down as CEO at the end of the year.

OxyChem is the chemical business of Occidental, in which Buffett is amajor investor. About $6.5 billion of the all-cash deal announced Thursday will be used to pay down Occidental’s debt, which has ballooned to more than $20 billion.

According to itswebsite, OxyChem makes a variety of chemicals that are used in IV bags, swimming pools and caustic soda, which is “central to the production of pulp, paper and aluminum, and is used in battery recycling.”

“OxyChem has grown under Occidental into a well-run, safely operated business with best-in-class employees, and we are confident the business and those employees will continue to thrive under Berkshire Hathaway’s ownership,” said Occidental CEO Vicki Hollub in a press release.

Shares of Occidental (OXY) rose less than 1% in premarket trading. The deal is expected to close in the fourth quarter of this year.