Warren Buffett's Berkshire Hathaway Inc. exited a $3.7 billion investment in Exxon Mobil Corp. amid a slump in oil prices.

Crude has fallen by about half since June as U.S. production surged and the Organization of Petroleum Exporting Countries resisted output cuts. The decline has ravaged oil company profits and forced major producers and drillers to slash spending and fire thousands of workers.

Berkshire has “not really had the hot hand in energy,” Fadel Gheit, an analyst for Oppenheimer & Co. in New York, said in a phone interview. “The whole energy sector obviously is now traded in completely different circumstances than they were only a year ago.”