UPDATE 1-Toronto stocks tumble on Lehman woes
*Oil shares slide with oil price on U.S. demand worry
*Gold rises on safe-haven buying; base metals slump
*Bank of Canada says will provide liquidity as required
TORONTO, Sept 15 (Reuters) - The Toronto Stock Exchange's main index plunged at the open on Monday, rattled by the bankruptcy filing of Wall Street's Lehman Brothers Holdings Inc LEH.N and worries over other major financial institutions.
Shortly after the open, the S&P/TSX composite index .GSPTSE was down 350.07 points, or 2.7 percent, at 12,419.51, with all of its 10 main groups lower.
The financial services sector, which accounts for about a quarter of the index's total weight, fell 2 percent with Canadian Imperial Bank of Commerce CM.TO down 3.2 percent at C$62.14.
Anxiety over the vulnerable U.S. financial sector heightened after a flurry of news from Wall Street, including the Lehman filing and a deal for Merrill Lynch MER.N to be taken over by Bank of America Corp (BAC.N: Quote). The U.S. Federal Reserve said that it would aid the battered financial industry.