* TSX ends up 53.78 points, or 0.45 percent, at 12,100.06 * Financials, materials, energy gain * Nine of 10 main sectors advance By Claire Sibonney TORONTO, Nov 21 Canada's main stock index rose for a fourth straight session on Wednesday to hit a one-week high, led up by financial stocks in a buildup to bank earnings and by gains in commodity shares on firm prices for oil and precious metals. The financial sector, the biggest on the index, advanced 0.6 percent on expectations of strong fourth-quarter bank earnings. Bank results will be released over the next two weeks, with Royal Bank of Canada the first to report, on Nov. 29. Analysts expect a year-over-year profit gain of more than 10 percent for the group, driven by stronger capital markets-related results. "The view is that you're going to have a pretty reasonable quarter, and that is being reflected in the price movement we've seen in the past several days," said Bob Gorman, chief portfolio strategist at TD Waterhouse. Bank of Nova Scotia was the most heavily weighted gainer on the index, rising 0.9 percent to C$54.25, followed by Toronto-Dominion Bank, up 0.6 percent at C$80.66. Royal Bank of Canada added 0.3 percent to C$57.59. The Toronto Stock Exchange's S&P/TSX composite index ended up 53.78 points, or 0.45 percent, at 12,100.06. Nine of its 10 main sectors were positive. Health care shares were off 0.2 percent. The index had opened lower after news that Greece's international lenders failed to strike a deal to release emergency aid, but politicians tried to give reassurance that a deal was close. Trading volume was healthy despite a holiday-shortened week in the United States. U.S. stock markets will be closed on Thursday for Thanksgiving and will close early, at 1 p.m. (1800 GMT), on Friday. Total volume on the Toronto Stock Exchange on Wednesday was around 280 million shares, comparable to the daily average last month. Energy shares were up 0.2 percent as oil prices ended higher after thin, volatile trading, and relief over a ceasefire that ended eight days of fighting between Israel and Hamas. Prices rose by more than $1.50 a barrel early in the day after an explosion on a Tel Aviv bus. But a truce announced at midday eased concerns that a week of intensive Israeli fire on the Gaza Strip and militant rocket attacks out of the enclave could widen, engulfing regional oil exporters. Still, Suncor Energy was one of top advancers, rising 0.8 percent to C$33.17, and Cenovus Energy climbed 1.5 percent to C$33.12. "It looks like we're seeing a little bit of a geopolitical premium building up in oil and I think there's definitely some headline risk from the Middle East over the next few weeks," said Youssef Zohny, portfolio manager at Stenner Investment Partners, a unit of Richardson GMP in Vancouver. The materials sector, which includes mining stocks, rose 0.7 percent, tracking firm precious metal prices. "Gold and silver are holding up pretty well, so it looks like there's a fairly decent bid in the commodity space and that's definitely helping the materials sector," Zohny said. Barrick Gold Corp, up 1.1 percent at C$34.63, Yamana Gold Inc, up 2.7 percent at C$19.21, and Goldcorp Inc, up 0.8 percent at C$40.96, were among the most heavily weighted gold miners on the upside.