TORONTO (Reuters) - The Toronto Stock Exchange's main index sagged yesterday, pressured by festering worries over the credit crisis and US economic outlook, which offset a rally in commodities.

The financial sector led the way down, dragged under along with US bank stocks after a forecast that US investment bank Lehman Brothers will take a further $4 billion in writedowns in the third quarter.

The forecast from JPMorgan Securities deepened worries over more fall-out to come from the credit crunch, taking Bay Street's bank sector down 3.2 percent. Among the decliners, Canadian Imperial Bank of Commerce slid three percent.

Sour economic data also injected a negative tone after data showed US wholesale prices shot up in July, while home builders cut back on construction. The data underscored worries of rising inflation and a housing market that continues to deteriorate.

The S&P/TSX composite index closed down 55.52 points, or 0.42 percent, at 13,063.85.

CIBC fell three percent to C$58.45, while Toronto-Dominion Bank lost 4.7 percent to C$59.

But a rebound in gold, oil and other commodities, while the US dollar weakened, cushioned the losses as advancing resource shares helped bring the Toronto benchmark back from a triple-digit loss.

The materials and energy sectors were the only two groups to make gains, rising 1.8 percent and 2.1 percent, respectively.

Canadian Natural Resources was up 3.3 percent at C$82.27, while Agnico-Eagle Mines climbed 4.5 percent to C$57.42.