* TSX falls 41.81 points, or 0.31 percent, to 13,377.76 * Seven of 10 main index sectors decline * BMO slips 3.6 percent, weighs most on market * Potash up after announcing job cuts By John Tilak TORONTO, Dec 3 (Reuters) - Canada's main stock index fell on Tuesday to its lowest in nearly three weeks as Bank of Montreal dropped after the company's results and concerns about the U.S. Federal Reserve's bond buying program weighed on overall sentiment. Shares of other major banks also fell as BMO, the country's No. 4 bank, was the first of the big lenders to report earnings this season. Recent positive economic data out of the United States, including upbeat manufacturing numbers on Monday, revived fears that the Fed might begin scaling back its monetary stimulus program sooner than later. The Toronto stock market on Tuesday snapped a four-session run of gains. In each of the past five months, the benchmark TSX index has advanced. "The market might be taking a bit of a breather, working off some of the overbought excesses over the last few weeks," said Stan Wong, vice president and portfolio manager at Richardson GMP Limited. "Going into the end of the year, (the TSX) might walk to the finish rather than sprint into the finish despite the fact that we are in the seasonally positive trend months." The Toronto Stock Exchange's S&P/TSX composite index was down 41.81 points, or 0.31 percent, at 13,377.76, after touching 13,331.10, its lowest level since Nov. 13. Seven of the 10 main sectors on the index were in the red. The financial sector gave back more than 1 percent. Royal Bank of Canada fell 0.9 percent to C$69.81, and Toronto Dominion Bank was down 0.9 percent at C$96.02. BMO, whose shares slipped 3.6 percent to C$70.87, said its quarterly earnings rose 1 percent after stronger wealth management results offset weaker income from the brokerage and U.S. Harris Bank units. "The important thing to look at is that BMO increased their dividend and they're doing a share buyback," said Wong, whose portfolio includes RBC and Bank of Nova Scotia. "I'm pretty constructive on the banks," added Wong. "The banks can benefit from an improving economy and the fact that investors are looking for visible yields that are also growing." Weighed by a weaker bullion price, gold-mining shares slipped 1.2 percent. Goldcorp Inc lost 1.1 percent to C$22.48, and Barrick Gold Corp declined 0.2 percent to C$16.50. In other news, Potash Corp of Saskatchewan Inc said it will cut its workforce by 18 percent as it struggles with slumping demand and weak prices for the crop nutrient. The stock advanced 0.2 percent to C$33.77.