Berkshire Hathaway Inc. said on Wednesday it has acquired more shares of Occidental Petroleum Corp., boosting its stake in the oil company to above 25 percent.

The conglomerate, controlled by billionaire Warren Buffett, said in a regulatory filing that it paid about $122.1 million for 2.14 million Occidental shares between June 26 and June 28.

Berkshire had also purchased about 4.66 million Occidental shares on May 30.

Buffett’s company began buying shares of Houston-based Occidental early last year, around when Russia invaded Ukraine and as oil prices were rising.

It also recently owned about $9.5 billion of Occidental preferred stock carrying an 8 percent dividend, plus warrants to buy another $5 billion of Occidental shares at $59.62 each. Berkshire bought the preferred stock and obtained the warrants in 2019 when it helped finance Occidental’s purchase of Anadarko Petroleum Corp.

At the annual shareholder meeting on May 6 in Omaha, Nebraska, Buffett praised Occidental’s management and business, but said Berkshire was not planning to acquire the company.

“We’re not going to buy control,” Buffett said. “We’ve got the right management running it.” Berkshire had amassed a 22.6 percent stake in the BNSF railroad before paying $26.5 billion for the remainder in 2010. BNSF now generates about one-fifth of Berkshire’s operating profit.

The share purchase comes at a time when insurance carriers in the U.S. and abroad are increasingly being scrutinized for their role in mitigating climate change.

Berkshire also owns dozens of other businesses including Geico car insurance and many energy, manufacturing and retail companies, as well as stocks such as Apple Inc.

(Reporting by Jonathan Stempel and Akanksha Khushi in Bengaluru; Editing by Sherry Jacob-Phillips)