* The Toronto Stock Exchange's TSX falls 0.40 percent to 20,504.15
* Leading the index were ARC Resources Ltd , up 4.8%, Tourmaline Oil Corp, up 4%, and Seabridge Gold Inc, higher by 3.3%.
* Lagging shares were Lithium Americas Corp, down 5.3%, Intertape Polymer Group Inc, down 2.6%, and Real Matters Inc, lower by 2.5%.
* On the TSX 107 issues rose and 119 fell as a 0.9-to-1 ratio favored decliners. There were 11 new highs and no new lows, with total volume of 159.4 million shares.
* The most heavily traded shares by volume were Suncor Energy Inc, Sun Life Financial Inc and Toronto-dominion Bank.
* The TSX's energy group rose 0.34 points, or 0.3%, while the financials sector slipped 3.56 points, or 0.9%.
* West Texas Intermediate crude futures fell 0.85%, or $0.58, to $67.78 a barrel. Brent crude fell 1.29%, or $0.93, to $71.32 [O/R]
* The TSX is up 17.6% for the year.
This summary was machine generated August 26 at 21:24.