Early hopes of an end to the brutal sell-off on North American stock markets quickly faded Friday as investors appeared unimpressed by White House efforts to revive a slumping U.S. economy.

The S&P/TSX composite index ended the day down 59 points to 12,737. That represented a dramatic turnaround from its early morning levels, when the benchmark index was up by 167 points.

S&P/TSX composite index 3-month chart

The tally brought the Toronto market's four-day plunge to a sobering 961 points — seven per cent of its value. Since the start of the year, the benchmark index has lost almost 1,100 points, or eight per cent.

The best that could be said about Friday's trading was that the drop was not of the triple-digit magnitude that had marked the three previous sessions.

Most sectors were in negative territory on Friday, with the financials, industrials, utilities, and metals and mining sectors leading the losers.

The Dow Jones industrial average was down 60 points at 12,099, a reversal of its early morning triple-digit gain. That brought the Dow's slide in the last four trading days to 679 points.

The Dow fell despite a better-than-expected profit outlook from IBM and a solid profit report from GE.

Morning comments about an economic stimulus package from U.S. President George W. Bush also failed to prompt a market rally.

Bush called for a package of tax rebates, business investment incentives and other measures that would be worth one per cent of U.S. GDP — in other words, about $145 billion US.

Nervous investors preferred to focus on the damage that a slowing U.S. economy would cause to companies' bottom lines. 

Laura Wallace, managing director Coleford Investment Management, said volatility is the norm these days and warned the selling may not be over.

"Momentum tends to take things further in whatever direction they're going," she told CBC News. "So it wouldn't be a surprise to see markets move lower over the next six weeks or so, until there's a clearer read on what's happening in the U.S. economy and the global economy."