The Nasdaq biotechnology index plunged more than 5 per cent, on track for its biggest one-day slump in nearly three years.
Other stocks bearing the brunt of the sell-off included Facebook and Netflix, both down about 5 per cent.
Solid US jobs data failed to help the mood on Wall Street today but did underscore the improved state of the labour market. Initial claims for state unemployment benefits dropped 32,000 to a seasonally adjusted 300,000 for the week ended April 5, according to the Labor Department. That was the lowest level since May 2007.
It turned out to be a good day for the US to auction US$13 billion in 30-year bonds.
"We've seen a significant retracement in equity prices, which spurred a flight-to-quality bid in the Treasuries markets," Ian Lyngen, a government-bond strategist at CRT Capital Group LLC in Stamford, Connecticut, told Bloomberg News.
In Europe, the Stoxx 600 Index ended the day with a 0.5 per cent drop from the previous close, as did Germany's DAX. France's CAC 40 fell 0.7 per cent. The UK's FTSE 100 bucked the trend, closing up 0.1 per cent. The Bank of England kept its benchmark interest rate at a record low today, as had been widely predicted.
China's exports and imports unexpectedly declined last month, data showed today. The country's overseas shipments fell 6.6 per cent from a year earlier, while imports slumped 11.3 per cent, boosting concern about sagging growth in the world's second-largest economy.
Even so, Chinese Premier Li Keqiang ruled out major stimulus to fight short-term dips in growth, saying that job creation was the government's policy priority, Reuters reported.
"We will not take, in response to momentary fluctuations in economic growth, short-term and forceful stimulus measures," Li said in a speech at an investment forum on the southern island of Hainan. "We will instead focus more on medium- to long-term healthy development."