Renewed weakness in the tech-heavy Nasdaq index in the U.S. roiled global markets Friday.

The Nasdaq index fell a further 54 points or 1.3 per cent to 4,000 after slumping three per cent on Thursday — its worst day since 2011 — as tech and biotech stocks took another hammering after a two-day recovery. The Nasdaq has been the main driver of global markets since last Friday when concerns over the valuation of many of its constituent stocks first erupted.

"There's a lot of pessimism in the markets right now," said Craig Erlam, market analyst at Alpari.

Following broad-based losses in Asia, where Japan's Nikkei suffered another big retreat, shares in Europe have fallen sharply. The FTSE 100 index of leading British shares was down 1.3 per cent at 6,551 while Germany's DAX fell 1.7 per cent to 9,294. The CAC-40 in France was 1.6 per cent lower at 4,344.

Wall Street as a whole was tracking the Nasdaq lower — the Dow Jones industrial average was down 143
points to 16,027 and had dropped 2.35 per cent on the week. The broader S&P 500 index fell 17 points to 1,815.

Disappointing earnings from JPMorgan Chase weighed on U.S. markets as the quarterly banking reporting season kicked off. JPMorgan fell 4 per cent in early trading.

In Toronto, the S&P/TSX composite index lost 50 points to 14,258. The Canadian dollar dropped .42 to 91.08 cents US.

Earlier in Asia, Tokyo's Nikkei 225 lost 2.4 per cent to close at 13,960.05 and South Korea's Kospi slipped 0.6 per cent to 1,997.44. Hong Kong's Hang Seng finished 0.8 per cent lower at 23,003.64 and China's Shanghai Composite shed 0.2 per cent to 2,130.54.

Elsewhere, the mood was fairly lackluster with the euro flat at $1.3887 and a barrel of benchmark New York crude 51 cents higher at $103.89.