US stocks are mostly lower in early trading; Amazon soars after reporting a surprise profit

U.S. stocks drifted mostly lower in early trading Friday as investors reviewed the latest batch of corporate earnings and deal news. Health care stocks were among the biggest decliners.

KEEPING SCORE: The Dow Jones industrial average fell eight points, or 0.1 percent, to 17,723 as of 10:13 a.m. Eastern Time. The Standard & Poor's 500 index slipped two points, or 0.1 percent, to 2,099. The Nasdaq composite gained seven points, or 0.1 percent, to 5,153.

REVENUE DRAG: Biogen Idec's second-quarter earnings beat Wall Street's forecasts, but the biotechnology company's revenue fell short. The stock slid $65.12, or 16.9 percent, to $319.93.

GETTING TOGETHER: Anthem has agreed to buy rival Cigna for $48 billion in a deal that would create the nation's largest health insurer by enrollment, covering about 53 million U.S patients. Investors did not immediately welcome the news. Anthem fell $4.56, or 2.9 percent, to $149.88, while Cigna lost $4.56, or 2.9 percent, to $150.75.

DELIVERING RESULTS: Amazon surged 16.1 percent a day after the e-commerce pioneer reported a surprise profit. The stock rose $77.66 to $559.73. Starbucks also served up strong earnings late Thursday. Its shares were up $1.91, or 3.4 percent, to $58.46.

MARKETS OVERSEAS: In Europe, Germany's DAX was down 0.5 percent, while the CAC-40 in France slipped 0.1 percent. The FTSE 100 index of leading British shares fell 0.4 percent. In Asia, investors were spooked by further evidence of a sizeable economic slowdown in China after a closely watched indicator of the country's manufacturing sector slumped to a 15-month low in July. China's Shanghai Composite Index sank 1.3 percent, while Hong Kong's Hang Seng shed 1.1 percent. Japan's Nikkei 225 fell 0.7 percent. Australia's S&P/ASX 200 fell 0.4 percent.

ENERGY: Benchmark U.S. crude was up 9 cents at $48.54 a barrel in New York. Brent crude was down 17 cents at $55.10 a barrel on the ICE futures exchange in London.

BONDS: U.S. government bond prices were little changed. The yield on the 10-year Treasury note held at 2.27 percent.