TORONTO -- North American stock markets sold off Thursday as weak trade data from China raised fresh questions about the pace of growth in the world's second-largest economy.

The declines were also fuelled by a fresh round of disenchantment with formerly high-flying biotech and technology stocks.

The S&P/TSX composite index fell 127.58 points to 14,308 as China's exports fell 6.6 per cent in March from a year earlier, well below analyst expectations of single-digit growth. Imports to China contracted by 11.3 per cent.

The Canadian dollar dropped 0.48 of a cent to 91.5 cents US.

U.S. markets tumbled while biotechnology companies fell sharply as Biogen Idec, Gilead Sciences and other biotech companies extended a recent slump. After making big gains last year, biotechs have been crushed in recent weeks as they come under pressure to lower prices for their drugs.

The Dow Jones industrials plunged 266.96 points to 16,170.22 while a selloff in tech stocks deemed too rich ahead of their first-quarter earnings pushed the Nasdaq 129.79 points lower to 4,054.11. The three per cent drop was the worst since November 2011.

"What is interesting is we are still seeing the Nasdaq pulling back more than the others so people are still retrenching out of the real high flyers," said Colin Cieszynski, senior markets analyst at CMC Canada.

"Tech does not look good and is looking like it's in a major correction."

Facebook dropped 5.2 per cent while Google retreated 4.1 per cent.

The S&P 500 index lost 39.09 points at 1,833.09, giving up its gains for the year.

The Chinese trade data raised worries the world's second-biggest economy will have trouble meeting its official target of 7.5 per cent growth this year. It also pushed some analysts to lower already reduced expectations for growth.

Barclays lowered its first-quarter gross domestic product forecast to 7.2 per cent year over year from 7.3 per cent.

Negative investor sentiment on U.S. markets spread to the TSX where the health care sector gave back 3.35 per cent with Valeant Pharmaceuticals (TSX:VRX) down $5.29 or 3.76 per cent to $135.36 .

Canadian tech stocks also helped push the TSX lower with BlackBerry (TSX:BB) down 28 cents to $8.38.

Financial stocks were also a major weight, down 1.06 per cent amid reduced earnings expectations for the big U.S. banks. Analysts at Thomson Reuters expect financial sector earnings to decline by 2.8 per cent and revenue to fall by one per cent.

The energy sector was 0.13 per cent lower while the sluggish Chinese data helped push the April crude contract on the New York Mercantile Exchange down 20 cents to US$103.40 a barrel.

Copper was up a cent to $3.05 a pound. The metal has already fallen 11 per cent this year amid lower expectations for Chinese economic growth. The base metals sector gave up early gains to move down 0.76 per cent.

The gold sector dropped about 1.4 per cent while bullion prices headed higher with the June contract up $14.60 to US$1,320.50 an ounce.

Shares in Goldcorp Inc. (TSX:G) dropped after it upped its offer for Montreal-based Osisko Mining Corp. (TSX:OSK), in an attempt to trump the gold miner's friendly deal with Yamana Gold announced last week. Goldcorp said its revised offer values Osisko at $3.6 billion or $7.65 per Osisko share. Goldcorp fell $1 to $26.84 while Osisko edged up three cents to $7.58.