Warren Buffett’s Berkshire Hathaway managed to buy as much as half of Occidental’s shares

Warren Buffett’s Berkshire Hathaway has the green light from regulators to buy as much as 50% of Western Petroleum Corp. its shares, after seeking approval for such a transaction in July.

In a regulatory filing Friday, the Federal Energy Regulatory Commission said Berkshire Hathaway had requested and received permission to buy up to 50% of the driller’s shares. Berkshire has loaded up on Occidental’s stock this year, amassing about 20% of the company’s shares, public filings show, leaving many analysts to speculate whether Mr. Buffett would seek control of the company, one of the largest U.S. oil producers.