US investors sent stocks lower yesterday, focusing again on technology issues.

The latest blow for tech stocks was Merrill Lynch's downgrade of the fibre optic industry, which had been seen as the last solid performer in the tech sector. And investors were still shaken by the renewed prospect of higher interest rates that would further cut into corporate earnings.

The Nasdaq composite index fell 133.61, or 4.2 per cent, to close at 3,031.88, and the Standard and Poor's 500 index was off 17.50, or 1.3 per cent, at 1,372.31. Both indexes have a large representation of high-tech stocks.

The Dow Jones Industrial Average finished down 51.57, or 0.5 per cent, at 10,656.03.