Warren Buffett's Berkshire announces surprise stake in embattled UnitedHealth
1. Berkshire Hathaway acquired 5 million shares in UnitedHealth Group. 2. UnitedHealth's stock rose 7% post-announcement, despite challenges. 3. Buffett previously sold his entire stake in 2010, amid challenges in healthcare. 4. UnitedHealth has recently faced increasing medical costs and federal investigations. 5. The company's profit forecast has significantly lowered due to rising costs.