Teva Pharmaceutical shares jumped 11 percent after Berkshire Hathaway reported a $358 million stake.
In a quarterly regulatory filing Wednesday, Warren Buffett's conglomerate reported holding 18.9 million ADRs of Teva. After spiking, Teva was still up more than 6 percent in after-hours trading.
At the same time, Berkshire has cut its holdings of IBM by 94 percent, to just more than 2 million shares. It also trimmed its Wells Fargo stake by 6 million shares to 458 million, and its stake in General Motors by 10 million shares, to 50 million.