* TSX down 9.50 points, or 0.07 percent, at C$13,371.20
* Seven of the 10 main groups lower
* U.S. markets closed on Friday
By Solarina Ho
TORONTO, Dec 23 (Reuters) - Toronto's main stock index closed marginally lower on Thursday with most sectors languishing in the red as trading slowed to a crawl ahead of the Christmas holidays.
The heavyweight financials group, which has gained in recent sessions, led all but three of the index's main groups lower. Bank of Montreal (BMO.TO) was the big decliner, down 1.38 percent at C$57.05. Manulife Financial (MFC.TO) was off 1.15 percent to C$17.21.
The Toronto Stock Exchange's S&P/TSX composite index .GSPTSE closed down 9.50 points, or 0.07 percent, at C$13,371.20.
"It's pretty quiet...We're just batting down for the holidays. The U.S. is closed tomorrow, so probably we're going to have the same sort of sleepy day tomorrow," said Levente Mady, market strategist at Union Securities.
Tempering losses was a modest 0.19 percent gain among materials stocks and a 0.05 percent advance in the energy group. Consumer staples was also in positive territory, up 0.17 percent.
Fertilizer giant Potash Corp (POT.TO) led gains, climbing 1.4 percent to C$145.91. Fellow fertilizer producer Agrium Inc (AGU.TO) also rose, rising 1.7 percent to C$86.87.
Oil and gas shares made some modest headway, with Canadian Natural Resources (CNQ.TO) up 0.5 percent at C$44.60, and Penn West Energy Trust PWT_u.TO up 1.37 percent at C$24.36.
"Oil is up a dollar, so it's not a big surprise energy's doing a little bit better and leading things along with some of the other materials," Mady said.
Oil prices surged above $91 a barrel to their highest level in more than two years on Thursday, buoyed by cold weather and depleted stockpiles. [O/R]
($1=$1.01 Canadian) (Reporting by Solarina Ho; editing by Peter Galloway)