Stock markets retreated Thursday as China's slowing economy forced Apple to slash its revenue forecast, wiping around $75 billion from the company's value and denting global investor sentiment.
Apple late on Wednesday cut its revenue outlook for the latest quarter, citing steeper-than-expected "economic deceleration" in China and emerging markets, factors that have contributed to sharp falls across stock markets since late last year.
Sentiment in the United States was further dented by Institute for Supply Management data showing US manufacturing activity at a two-year low. The data still showed growth but suggested the United States was seriously affected by a slowing global economy and trade tensions.
The rare revenue warning from Apple pointed to weaker-than-anticipated sales of iPhones and other gadgetry, in part because of trade frictions between Washington and Beijing.
Apple finished down 10 percent, ending with a market value of just under $675 billion, far from the landmark $1.0 trillion level it reached in August.
US stock indices were also hard hit, with the Dow ending at 22,686.22, down 660 points, or 2.8 percent.
Tech companies with steep falls included Intel, which slumped 5.5 percent, while shares in Franco-Italian group STMicroelectronics dived 9.7 percent and Germany's Infineon shed around five percent.
"For a while now there's been an adage in the markets that as long as Apple was doing fine, everyone else would be OK. Therefore, Apple's rare profits warning is a red flag for market watchers," noted Neil Wilson, chief market analyst at Markets.com.
"A lot of this is Apple specific (...). But the warning also tells a lot about what is happening on in the broader global economy, specifically China. It tells us that China is experiencing a period of softness," he added.
"We're heading to the earning season," said Adam Sarhan of 50 Park Investments. "The fact that Apple, one of the largest companies in the world, lowers guidance basically means other companies are going to lower it as well."
White House economist Kevin Hassett said Apple was not alone, telling CNN there were "a heck of a lot of US companies" exposed to the Chinese market that were likely to see earnings downgraded until Washington and Beijing resolved their differences on trade.
- Surging yen -
Apple's warning contributed to a rally by the Japanese yen, which tends to benefit from a "flight to safety" when investor anxiety is high.
The yen surged nearly four percent against the dollar before the greenback recovered somewhat.
The Japanese unit also reached a 10-year high against the Australian dollar, which is seen as a bellwether for China.
The Aussie has been battered by slowing growth in China, a key export destination for the country's commodities sector.
"The moves were very violent," said Stephen Miller, an adviser at Grant Samuel Funds Management.
In other corporate news, New York-based pharmaceutical giant Bristol-Myers Squibb announced it would buy US biotech firm Celgene in a $74 billion cash and stock deal to create a specialized biopharmaceutical company.
Shares in Bristol-Myers shares dropped 13 percent -- while the New Jersey-based Celgene spiked 20.7 percent.
- Key figures around 2200 GMT -
New York - Dow: DOWN 2.8 percent at 22,686.22 (close)
New York - S&P 500: DOWN 2.5 percent at 2,447.89 (close)
New York - Nasdaq: DOWN 3.0 percent at 6,463.50 (close)
London - FTSE 100: DOWN 0.6 percent at 6,692.66 (close)
Frankfurt - DAX 30: DOWN 1.6 percent at 10,416.66 (close)
Paris - CAC 40: DOWN 1.7 percent at 4,611.48 (close)
EURO STOXX 50: DOWN 1.3 percent at 2,954.66 (close)
Hong Kong - Hang Seng: DOWN 0.3 percent at 25,064.36 (close)
Shanghai - Composite: FLAT at 2,464.36 (close)
Tokyo - Nikkei 225: Closed for public holiday
Dollar/yen: DOWN at 107.63 yen from 108.88 yen at 2200 GMT on Wednesday
Euro/dollar: UP at $1.1394 from $1.1344
Pound/dollar: UP at $1.2637 from $1.2607
Oil - Brent Crude: UP $1.04 at $55.95 per barrel
Oil - West Texas Intermediate: UP 55 cents at $47.09 per barrel