The biggest contributor to the TSX loss was Suncor Energy, and energy was the biggest drag among sectors.

Leading the index were Aphria Inc , up 5.4 percent, Canopy Growth Corp , up 5.3 percent, and Aurora Cannabis Inc  , higher by 4.8 percent.

Lagging shares were Precision Drilling Corp , down 5.1 percent, Shopify Inc, down 4.7 percent, and Cenovus Energy Inc, lower by 4.6 percent.

On the TSX 85 issues advanced and 154 declined as a 0.6-to-1 ratio favored decliners. There were 12 new highs and 5 new lows, with total volume of 196.6 million shares.

The most heavily traded shares by volume were Aurora Cannabis Inc , Canopy Growth Corp  and Aphria Inc.

The TSX's energy group  fell 3.95 points, or 1.99 percent, while the financials sector climbed 0.37 points, or 0.12 percent.

West Texas Intermediate crude futures rose 0.03 percent, or $0.02, to $65.73 a barrel. Brent crude  fell 2.21 percent, or $1.65, to $73.09 [O/R]

The TSX is up 0.8 percent for the year.

(Reporting by Caroline Valetkevitch)