Warren Buffett’s Berkshire Hathaway Inc has bought another 5.9 million shares of Occidental Petroleum Corp, boosting its stake in the oil company to about 15.2%.

The purchases were made on Monday and Tuesday and cost about $336 million, Berkshire said in a regulatory filing on Wednesday night.

Following the purchases, Berkshire owned about 142.3 million Occidental shares worth approximately $8.8 billion, plus $10 billion of preferred stock it acquired in 2019 to help finance Occidental’s purchase of Anadarko Petroleum Corp.

Read more: Reuters