* TSX ends down 144.28 points, or 1.1 pct, at 12,939.72
* Index close lowest since Nov. 29, 2010
* S&P cuts Greece to CCC, or 8 notches into junk
* All 10 index sectors weaker (Updates to close)
By Claire Sibonney
TORONTO, June 13 (Reuters) - Toronto's main stock market closed below 13,000 on Monday for the first time since November as a downgrade of Greece's credit rating prompted more economic pessimism and a drop in commodity prices.
Greece's credit rating became the lowest of any country in the world after Standard & Poor's downgraded it by three notches, saying the agency would consider any debt restructuring as a default. [ID:nN13126859]
The news sent oil prices tumbling with U.S. crude oil futures ending almost $2 a barrel lower, pushing Toronto's energy shares down almost 2 percent. [O/R]
Brian Pow, a research and equity analyst at Acumen Capital Partners in Calgary, said the euro zone woes, as well as fears of slowing growth in China, were contributing to investors' anxiety.
"People are just moving their risk capital to safer havens and trying to stand back and see what comes out of this," he said.
"I'm of a view we're in a sideways market so we could possibly go lower but ... as the volumes pick up again and as companies report some of their Q2 numbers later in the summer, I think it will prove that some of this current concern is not needed."
The Toronto Stock Exchange's S&P/TSX composite index .GSPTSE ended down 144.28 points, or 1.1 percent, at 12,939.72, its lowest close since Nov. 29.
The selloff saw the TSX break through key psychological support at 13,000 -- for the first time since Dec. 1.
All of the the index's 10 main sectors were weaker, including financials, which dipped 0.2 percent. Among bank stocks, Bank of Nova Scotia (BNS.TO) was the worst performer, down 1.2 percent at C$56.90.
Heavyweight miners were dragged lower by weaker metal prices. Goldcorp Inc (G.TO) was the index's most influential decliner, losing 2.5 percent to C$45.05. Silver Wheaton SLW.TO plunged 5 percent to C$29.88, and First Quantum Minerals (FM.TO) dropped 1.9 percent to C$117.81. [GOL/]
Bucking the broader trend, TMX Group (X.TO) rose 0.9 percent to C$43.19 after Maple Group filed a formal C$3.7 billion hostile takeover bid for the exchange operator. [ID:nN13101866]
$1=$0.98 Canadian Editing by Jeffrey Hodgson