(Updates with official closing numbers, adds detail)
TORONTO, Jan 15 (Reuters) - The Toronto Stock Exchange's main index plunged on Tuesday, hammered by slumping resources and and financials, amid more writedowns in the banking sector from both sides of the border.
Heightened fears of a U.S. recession, declining commodity prices and massive writedowns from Canadian Imperial Bank of Commerce (CM.TO) and U.S. bank Citigroup (C.N) helped drag the index to its biggest one-day loss in more than five months.
The S&P/TSX composite index .GSPTSE closed down 381.50 points, or 2.79 percent, at 13,316.78, with all 10 of its main sectors lower.
CIBC, Canada's fifth-biggest bank, shed C$2.07, or 2.9 percent, to C$70.00 the day after it said it would issue C$2.75 billion in new shares and take additional pretax writedowns of $2.46 billion for U.S. subprime mortgage-related securities.
The financial sector, which fell 2.3 percent, was also stung by Citigroup's record $9.83 billion quarterly loss.
The biggest U.S. bank also said it would raise $14.5 billion in new capital, cut its dividend and slash 4.200 jobs to shore up its balance sheet.
Resource issues also fell amid worries that a U.S. recession could spark a global slowdown and slash demand for resources.
The energy and materials sectors lost 3.5 percent and 3.9 percent respectively as oil and gold prices both retreated amid jitters over the health of the U.S. economy after data showed a decline in U.S. retail sales.
$1=$1.02 Canadian Reporting by Leah Schnurr; editing by Rob Wilson