New York - Apple rose early on Monday following news of an investment in the tech giant by Warren Buffett, helping to push US stocks higher.
Apple jumped 2.4% as Buffett's Berkshire Hathaway disclosed about a $1bn stake in Apple.
Economic data in China was lackluster, with industrial production and retail sales rising less in April than they had in March.
About 30 minutes into trade, the Dow Jones Industrial Average was at 17 608.36, up 0.4%.
The broad-based S&P 500 gained 0.4% at 2 054.27, while the tech-rich Nasdaq Composite Index advanced 0.5% to 4 743.24.
Anacor Pharmaceuticals, a California biotech firm, shot up 54.5% on news it reached a deal to be bought by pharma giant Pfizer for $5.2bn. Dow member Pfizer was flat.
Yahoo rose 2.2% following reports that Buffett is backing a bid from an investment consortium to acquire Yahoo's core assets.
Petroleum-linked shares bounced on higher oil prices. Apache, EOG Resources, Halliburton and Baker Hughes all rose more than 2.0%.
Natural gas producer Memorial Resource Development jumped 7.7% following news it agreed to be acquired by Range Resources for $4.4bn. Range sank 7.0%.