The S&P/TSX composite index fell 24.32 points to 12,232.86, rebounding slightly from an earlier loss of more than 80 points. The TSX Venture Exchange shed 6.35 points to 1,306.86.
The Canadian dollar fell 0.48 of a cent to 101.50 cents U.S. as commodity prices failed to get a lasting boost from an improvement Tuesday in U.S. consumer confidence to its highest level since February.
Wall Street markets were also lower, with the Dow industrials average down 44.04 points to 13,413.51, the Nasdaq off 24.03 points at 3,093.70. The broader S&P 500 index was down 8.27 points to 1,433.32.
A day after U.S. stocks suffered their biggest retreat in three months on comments from a leading official at the U.S. Federal Reserve, investors were spooked Wednesday by scenes of violent protests in Athens and Madrid that reignited concerns over Europe's ability to implement the measures needed to deal with its debt.
The developments in Europe overshadowed some mildly encouraging data on the state of the U.S. housing market.
The median price of new homes sold in August rose by a record amount, while sales of new homes dipped slightly. Sales in August were up 27.7 per cent from a year earlier, but remain at about half the pace economists consider healthy.
Stronger data on the U.S. housing market have insulated stocks in recent weeks from a slackening global economy. The other main source of support has been the Federal Reserve's program to boost the economy by pumping money in. That idea lost some lustre Tuesday after a key Fed official said he doubted it will do much good.
But investors were more focused on Europe than on the U.S. housing market news, said Gavin Graham, president of Graham Investment Strategy Ltd.
"We may finally be starting to see the turn in what's been a major drag on growth," he said.
"Maybe now we're starting to see a little bit of positive news but that's obviously more of a long-term story. In the meantime when you have rioting crowds in the streets that tends to rather focus people's attention."
If there are continued worries about Europe being able to achieve a successful resolution to its debt crisis, that could worsen the recession across the Atlantic, lowering demand for commodities, which make up a big portion of the companies on the TSX, he explained.
The benchmark New York oil contract was $1.39 lower at $89.98 a barrel, the December gold contract slipped $12.80 to $1,753.60 an ounce and the December copper contract fell five cents to $3.71 a pound.
The mining sector was the biggest drag on the TSX as it lost 1.3 per cent with shares in HudBay Minerals (TSX:HBM) down two per cent or 19 cents to $9.46. That was followed by the energy sector, which fell 0.84 per cent with shares in Suncor Energy (TSX:SU) down 22 cents to $32.01.
In Canadian economic news, the Conference Board said consumer confidence improved this month, following a weak showing in August. The Ottawa-based economic forecaster said its consumer confidence index increased 6.7 points to 82.2.
And in Canadian deals, Onex Corp. (TSX:OCX) is leading a $718-million bid to acquire a German manufacturing company, the first European investment for the Toronto-based company's flagship private equity fund. Onex shares added 13 cents to $38.20.
CGI Group (TSX:GIB.A) has received a five-year contract worth up to US$871 million from the Defense Information Systems Agency. Shares in the company dropped 1.7 per cent 45 cents to $26.38.
Investment manager AGF Management Ltd. (TSX:AGF.B) reported a loss of $13.3 million or 14 cents per share in the quarter ended Aug. 31 compared with a profit of $15.4 million or 16 cents per share a year ago. Shares fell nine per cent or $1.13 cents to $11.30.
And shares of Research In Motion Ltd. (TSX:RIM) gained six per cent or 38 cents to $6.88. The move higher followed comments from RIM's chief executive Thorsten Heins, who told a developer conference Tuesday that RIM has grown its user base to about 80 million at the end of its second quarter.
That's up from 78 million in the previous quarter. RIM is scheduled to report its second-quarter financial results on Thursday after market close.
A DBRS report released Wednesday said the net benefit of a $15.1-billion takeover of Nexen Inc. (TSX:NXY) by a Chinese company is "somewhat mixed" because the deal offers only limited direct financial benefits but may help trade relations. Shares in Nexen rose 18 cents to $24.91.