TORONTO (Bloomberg) - Canadian stocks gained the most in a week, led by banks, after Canadian Imperial Bank of Commerce posted lower-than-estimated writedowns, stoking speculation that the worst of the credit crisis may soon be over for lenders.

CIBC jumped the most since July 17, lifting an index of banks and insurance stocks from a six-week low. Canadian Natural Resources Ltd. and Potash Corp. of Saskatchewan Inc. paced gains among commodity producers, as oil, metals and grain prices rose and the US reported an increase in durable-goods orders.

The Standard & Poor's/TSX Composite Index jumped 1.7 percent to 13,530.65 in Toronto. Canada's equity benchmark, which derives three-quarters of its value from financial, energy and materials and stocks, has still dropped 10 percent from its June peak as commodities slumped on concern credit losses would slow global growth and demand for resources.

"This might not be the bottom yet for" CIBC, said Michael Sprung, president of Sprung & Co. Investment Counsel, which manages about $50 million in Toronto. "But it's certainly close enough. We're beginning to see some attractive valuations."

Canadian Imperial Bank of Commerce (CIBC) gained 5.3 percent to C$60.10. The country's fifth-largest bank had C$885 million in pretax writedowns linked to the US mortgage market, adding to the C$6.66 billion in debt-related costs it's reported since the third quarter of 2007.

Canadian Imperial said third-quarter profit fell 91 percent to C$71 million ($68 million) on the writedowns. CIBC earned C$1.65 a share before some one-time items, said National Bank Financial analyst Robert Sedran, missing his C$1.72 estimate.

CIBC was raised to "neutral" from "sell" by John Aiken at Dundee Securities Corp. in Toronto, who said that its writedowns were "well below" his estimate of as much as C$1.9 billion. This should allay concern that the company may have to raise capital by selling additional shares or cutting the dividend, the analyst wrote in a note. He kept his share-price target of C$49 under review.