Berkshire had built up the stake in addition to its $10 billion investment in preferred shares last year, which helped fund Occidental’s ill-fated takeover of Anadarko Petroleum Corp. It also received its most-recent $200 million-a-quarter dividend from the preferred shares in common stock.

That Berkshire no longer shows a stake in Occidental, revealed in a regulatory filing Friday, indicates that Buffett has been selling the common stock he received as dividends to reduce his overall exposure to the Houston-based oil producer.

Occidental has tumbled 64% this year, making it the worst performer in the S&P 500 Energy Index.