(Updates throughout with market moves, reaction to earnings, analyst comments)
* TSX down 51.48 points, or 0.36 percent, to 14,255.64
* Half of the TSX's 10 main groups fell
By Solarina Ho
TORONTO, July 23 (Reuters) - Canada's main stock index was headed for its fifth straight decline on Thursday as losses by the main financials, energy and materials sectors offset gains from companies reporting positive quarterly results.
U.S. crude prices were mostly flat but remained below $50 a barrel, levels that kept the pressure on energy shares, which were down 1.0 percent.
Suncor Energy Inc led with a retreat of 1.19 percent to C$33.15, followed closely by Enbridge Inc, which fell 1 percent to C$55.18.
"Oil prices breaking through $50 certainly was hurting ... (and) will be tough to navigate through," said Brian Pow, vice president, research, at Acumen Capital Partners in Calgary. "Just in terms of (Canadian) dollar weakness, it's making people question what they want to do."
At 11:03 a.m. EDT (1503 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 51.48 points, or 0.36 percent, at 14,255.64.
Of the index's 10 main groups, half were in negative territory. Materials, which include mining companies, were down 1.6 percent, while financials were off 0.64 percent. The two groups, combined with oil and gas stocks, make up roughly two-thirds of the TSX's weight.
"I think it's going to be very earnings-driven," said Pow. "It's a sloppy market because it's summer time. But yes, people will be focusing on some of the bigger names to see how they perform."
Drugmaker Valeant Pharmaceuticals International Inc had the biggest positive impact on the TSX, with shares rising 3.69 percent to C$323.77 after it reported a higher-than-expected quarterly profit. Strength in its U.S. dermatology business bolstered results.
Canada's largest grocer, Loblaw Cos Ltd, climbed 2.84 percent to C$69.47 after it also posted upbeat results and said it would be closing more than 50 stores, a move expected to help future earnings.
Rogers Communications Inc rose 1.60 percent to C$44.53 after the company said it added wireless accounts in the second quarter, marking progress as it seeks to fix customer service and billing as part of a broader strategic overhaul.
Declining issues outnumbered advancing ones on the TSX by 2.16 to 1. Five stocks in the index set 52-week highs, and 18 set year lows. (Reporting by Solarina Ho; Editing by Lisa Von Ahn)