US stocks fell for fourth straight day on Friday, with investors spooked by an inexplicable crash the day before and by ongoing concerns over Greece’s debt situation.

Sharp losses of more than five per cent this week pushed all three major stock indices into negative territory for the year, erasing hard—fought gains that came on the back of signs that the United States was recovering better than expected from a deep recession.

The stock market’s electronic trading mechanisms remained under scrutiny after chaos erupted on the trading floor Thursday. The Dow Jones Industrial Average suddenly plummeted nearly 1,000 points in the afternoon before recovering much of the ground minutes later.

President Barack Obama said regulators were investigating the trading anomaly.

Also on Friday, leaders of the 16—member eurozone were meeting in Brussels, as investors still looked warily at Greece’s debt crisis and the potential that it could spread to other countries.

The stock trading and euro concerns overshadowed the best monthly US jobs figures in four years. The Labour Department said companies added 290,000 jobs in April, with most of the gains stemming from the private sector. Job gains for February and April were also revised upwards by 121,000 in total.

But the unemployment rate climbed to 9.9 per cent, from 9.7 per cent in the first three months of 2010, as more than 800,000 people who had given up looking for work re—entered the labour market.

The blue—chip Dow closed on Friday down 139.89 points, or 1.33 per cent, to 10,380.43. The broader Standard and Poor’s 500 Index fell 17.27 points, or 1.53 per cent, to 1,110.88. The technology—heavy Nasdaq Composite Index tumbled 54 points, or 2.33 per cent, to 2,265.64.

For the week, the Dow plummeted 5.71 per cent, the S&P 500 plunged 6.39 per cent and the Nasdaq sunk 7.95 per cent. All three indices have now fallen less than 0.5 per cent since the start of 2010.

After days of strong gains, the US currency fell to 78.51 euro cents from 79.01 euro cents, a 14—month high, on Thursday. The dollar also gained against the Japanese currency to 91.53 yen from 90.56 yen the previous day.

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