The Toronto stock market piled on losses for a fourth session Wednesday, pressured by commodity stocks on doubts the spring rally has much momentum left.

The main S&P/TSX composite index fell 241.29 points to 10,066.11 as energy and mining stocks continued to retrench after helping boost the Toronto market as much as 40 per cent since the rally began in early March.

In the past four sessions, 648 points or almost 6.5 per cent have been carved from the index and opinion is divided on how much markets more could retreat.

Eric Brass, equity analyst at MFC Global Investment Management, said calling short-term moves in a market like this is next to impossible.

"One thing we do expect, can almost bet on, is we expect the market to remain pretty volatile going forward. So you will see a little bit more ups and downs than actually a set pattern going forward," Brass said.

On Wednesday,the energy sector fell 3.5 per cent with the July crude contract on the New York Mercantile Exchange moved up 56 cents at US$71.03 a barrel.

Suncor Inc. (TSX:SU) declined $1.88 to $34.30.

The TSX Venture Exchange moved 23.82 points lower to 1,115.37 while the Canadian dollar reversed direction to move up 0.28 of a cent at 88.42 cents US.

New York markets were mainly flat on economic concerns, a disappointing outlook from FedEx Corp. and a downgrade of 18 banks by ratings agency Standard & Poor's

The Dow Jones industrial average was 7.49 points lower to 8,497.18.

The Nasdaq composite index gained 11.88 points to 1,808.06 while the S&P 500 index slipped 1.26 points to 910.71 after FedEx (NYSE:FDX) said it posted a fiscal fourth-quarter loss and forecast earnings well below analysts' views in the next quarter. Its shares were down 72 cents to $50.70.

Investors also reviewed the White House's plan for remaking the rules that govern Wall Street. The changes would award new powers to the U.S. Federal Reserve and establish a consumer protection agency.

Elsewhere, Standard & Poor's cited concerns that volatility will remain in the financial industry and that banks are expected to face tighter regulatory oversight. The agency also said loan losses could grow beyond what many analysts expect.

Investors also took in news of lower than expected U.S. inflation, lower Canadian wholesale sales and an improvement in an important gauge in future economic activity.

The U.S. Labour Department said the consumer price index increased a seasonally adjusted 0.1 per cent in May, below analysts' expectations of a 0.3 per cent rise.

Statistics Canada said wholesale sales fell 0.6 per cent to $40.3 billion in April.

And the rate of decline of the leading indicator slowed markedly to 0.1 per cent in May, the smallest of nine straight drops.

The base metals sector was a major weight on the TSX, down almost five per cent. Teck Resources (TSX:TCK.B) fell 95 cents to $17.32.

Ivanhoe Mines (TSX:IVN) shares lost 60 cents to $6.28 amid a report that Mongolia's president-elect wants to change a proposed gold and copper mining agreement with that company and Rio Tinto.

Shares in PotashCorp. (TSX:POT) tumbled $12.66 or 10.5 per cent to $108.34 after it said Tuesday it would reduce 2009 production by 800,000 tonnes, but expects demand to pick up in the second half of this year.

Meanwhile, Agrium Inc. (TSX:AGU) said Tuesday that shareholder firm RiskMetrics Group is recommending CF Industries Holdings Inc. (NYSE:CF) stockholders approve its more than US$4-billion takeover of the fertilizer company. Calgary-based Agrium said the deal, which values CF at US$88.20 per share based on Tuesday's closing price, "is far superior to any alternative." Agrium shares dropped $3.76 to $48.49.

After a six-month shutdown, uranium giant Cameco Corporation (TSX:CCO) said Wednesday it has resumed production at its Port Hope, Ont. uranium conversion plant. Its shares were down 50 cents to $28.32.

The August bullion contract on the Nymex rose $3.80 to US$936 an ounce and the gold sector drifted 0.3 per cent lower.

The financial sector also gave up ground, down 1.7 per cent with Manulife Financial Corp. (TSX:MFC) down 89 cents to $22.51.

In other corporate news, TransCanada Corp. (TSX:TRP) shares declined $1.69 to $31.37 after it said Tuesday it is buying the remaining stake in the Keystone pipeline from U.S. energy giant ConocoPhillips for $550 million.