* TSX down 50.73 points, or 0.33 percent, at 15,093.14
* Seven of the TSX's 10 main groups move lower
TORONTO, Aug 1 (Reuters) - Canada's main stock index fell on Tuesday as falling energy stocks helped outweigh gains for companies reporting strong earnings, including airline Air Canada and e-commerce company Shopify Inc.
The heavyweight energy group, which accounts for one-fifth of the index's weight, retreated 0.8 percent as crude prices slipped from a two-month high, with major oil producer Suncor Energy Inc down 1.8 percent at C$39.95.
Large banks and miners also dragged the index lower despite Air Canada surging to an all-time high after its second-quarter profit handily beat analysts' estimates. The stock was last up 10 percent at C$21.81.
Its smaller rival, WestJet Airlines Ltd, also topped expectations, and its shares gained 4.4 percent to C$25.93.
Shopify, the Ottawa-based company that counts Procter & Gamble Co among its customers, jumped 11.7 percent to C$128.35 after reporting a smaller-than-expected loss and a 75 percent jump in revenue.
Toronto-based Thomson Reuters rose 4.4 percent to C$59.59 after the information services provider reported higher-than-expected second-quarter earnings, helped by demand for market data, and increased its full-year forecast for margins and adjusted earnings per share.
Decliners outnumbers advancers by a two-to-one ratio overall, with seven of the index's 10 main groups in the red.
At 9:48 a.m. ET (1348 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 50.73 points, or 0.33 percent, at 15,093.14.
The materials group, which includes precious and base metals miners and fertilizer companies, lost 0.7 percent, while the financials group slipped 0.2 percent.
Those two groups and the energy sector collectively account for almost two-thirds of the index's weight.
(Reporting by Alastair Sharp; Editing by W Simon)