Traders were also cautious ahead of the release of the June U.S. non-farm payrolls report before the markets open Friday morning.
The S&P/TSX composite index snapped a six session rally and lost 96.96 points to 11,816.91 while the TSX Venture Exchange was down 15.45 points to 1,226.45.
The European Central Bank and the People's Bank of China both cut interest rates while the Bank of England embarked on another round of quantitative easing. This involves pumping money into the economy which, hopefully, will be lent to businesses and consumers.
But early enthusiasm faded as ECB president Mario Draghi warned that further risks to euro-area growth have materialized, pointing to signs of slower growth and greater uncertainty in the second quarter. Meanwhile, a reading of the U.S. service sector increased worries that the American economy is stalling.
The Canadian dollar was off 0.12 of a cent to 98.58 cents US.
U.S. markets were mainly lower as positive employment data competed with a worse than expected performance of the service sector.
The Dow Jones industrial average dropped 47.15 points to 12,896.67 as the Institute for Supply Management's service sector index moved closer to contraction, coming at 52.1, down from 53.7 in May. That’s the lowest reading since January 2010. U.S. service companies employ roughly 90 per cent of the economy.
The Nasdaq composite index added 0.04 of a point to 2,976.12 while the S&P 500 index was down 6.44 points to 1,367.58.
Payroll firm ADP reported that the U.S. private sector created 176,000 jobs during June. Expectations for Friday's report are modest with economists forecasting the economy only cranked out about 90,000 jobs during June.
"I think that this is kind of a wait-and-see moment for the market," said Craig Fehr, Canadian markets strategist at Edward Jones in St. Louis.
"We have a lot of central bank news out today, the market's clearly going to stay suspended ahead of the U.S. jobs report tomorrow, which I think will probably provide the true direction for the markets this week."
Markets had already largely priced in the European moves, helping to spark a sharp run-up in equities over the past few sessions. The TSX, meanwhile, had gained more than five per cent in the last six trading days.
But traders were surprised by the China central bank's move to cut its benchmark lending rate by 0.31 of a point to six per cent. It is the second time within a month the bank has cut interest rates in an attempt to stimulate China's rapidly slowing economy. But the move caused some investors to worry that the downturn in the world’s second-largest economy may be worse than previously expected.
The Bank of England announced it was injecting another 50 billion pounds into the ailing British economy, which has been officially in recession. The move by the Bank of England's Monetary Policy Committee involves the bank purchasing government bonds from banks. It was widely-anticipated and raises the amount it is pumping into the British economy since March 2009 to 375 billion pounds. It is the first stimulus since February.
The European Central Bank weighed in with a quarter-point cut in its key rate to an all time low of 0.75 per cent.
All TSX sectors were negative and energy stocks led declines as oil prices were in the red despite data which showed U.S. crude inventories fell by 4.3 million barrels last week. Prices had briefly moved into positive territory after the release of the report as it raised hopes for higher demand.
The August crude contract on the New York Mercantile Exchange declined cents to US$ a barrel. Oil is still up about US$10 from last Thursday, partly over increased tensions with Iran. But traders have also been hopeful that central bank action to boost economic growth.
The energy sector dropped 1.71 per cent while Suncor Energy (TSX:SU) gave back 73 cents to $30.40 and Canadian Natural Resources (TSX:CNQ) declined 79 cents to $27.54.
The gold sector was off about one per cent as gold prices relaxed $12.40 to US$1,609.40 an ounce. Goldcorp Inc. (TSX:G) faded $1.04 to $39.30 while Kinross Gold Corp. (TSX:K) dropped 33 cents to $8.81.
The industrials sector gave back 0.8 per cent as Canadian National Railways (TSX:CNR) dropped $1.76 to $85.59.
The base metals sector shed 0.36 per cent while September copper lost five cents to US$3.49 a pound, but prices are still up about 4.5 per cent from last Thursday. Inmet Mining (TSX:IMN) gave back $1.09 to $43.02 while HudBay Minerals (TSX:HBM) gained 22 cents to 48.63.