Global stocks slid lower on Friday and were set for their worst week in more than five years, as anxiety over corporate profits added to fears about global trade and economic growth.
European shares tracked U.S. stock futures lower after Alphabet and Amazon's earnings missed expectations, further sapping risk appetite as European earnings also disappointed.
The leading index of euro zone stocks fell 1.5 percent. Germany's DAX was down 1.7 percent and France's CAC 40 down 1.8 percent.
The MSCI All-Country World Index, which tracks shares in 47 countries, was down 0.3 percent after trading began in Europe. It was set for its fifth straight week of losses, its worst losing streak since May 2013.
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"Expectations for U.S. company earnings are quite high, so whenever they are not being met, the reactions are quite severe," said Miraji Othman, credit strategist at BayernLB.
"We have grown used to solid numbers, 18 percent revenue growth, 25 percent revenue growth and so on. The valuations have become quite ambitious."
S&P E-mini futures slumped 0.84 percent, potentially setting up a rough session for U.S. markets.
MSCI's broadest index of Asia-Pacific shares outside Japan dropped 0.9 percent, erasing gains made in the opening hour and hitting its lowest level since February 2017. The Chinese yuan slid past a key level, refocusing attention on slowing growth in the world's second-biggest economy.
The MSCI Asia index has been bruised by a sell-off in the past several days, and is on course for its fifth weekly loss — its longest losing streak since 2015. It has fallen more than 4 percent this week.
Chinese shares were pulled lower and the yuan fell past 6.96 to the dollar, touching its weakest level against the dollar since December 2016. Tech firms also fell in South Korea, where the broader market slid 1.75 percent. Japan's Nikkei stock index closed 0.4 percent lower, ending the week down 5.98 percent.
Financial markets have been whipsawed in recent sessions amid concern over global growth created by U.S.-China trade frictions, a mixed bag of U.S. corporate earnings, Federal Reserve rate increases, and an Italian budget dispute.
"The first, and most important (worry) is that Fed tightening and fading fiscal stimulus will cause the U.S. economy to take a turn for the worse... The second is that China's economy will continue to struggle," analysts at Capital Economics said in a note to clients.
"As we have been arguing for a while now, these worries are likely to get worse over the next twelve months or so."