* TSX down 78.33 points, or 0.5 percent, to 15,541.32
* Nine of TSX's main groups lower
TORONTO, May 3 (Reuters) - Canada's main stock index retreated on Wednesday as lower industrial metal prices weighed on most miners, although strong quarterly results from two mining companies tempered some of the losses.
The overall materials group, which includes precious and base metals miners and fertilizer companies, lost 0.8 percent, tracking falls in base metals, including copper and nickel. Copper prices declined 3.5 percent to $5,601.50 a tonne.
Teck Resources Ltd declined 5.9 percent to C$26.60, while First Quantum Minerals Ltd declined 5.4 percent to C$12.03.
Kinross Gold Corp and Tahoe Resources Inc offset some of the losses and were among the most positive influential movers after the gold miners reported strong results late Tuesday. Kinross jumped 12.2 percent to C$5.15, while Tahoe surged 12.5 percent to C$12.07.
Home Capital Group Inc sank 8.9 percent to C$7.06 after the troubled non-bank lender delayed its first-quarter results. The overall financials group, which accounts for about one-third of the index, fell 0.3 percent.
At 11:05 a.m. EDT (1505 GMT), the Toronto Stock Exchange's S&P/TSX composite index fell 78.33 points, or 0.5 percent, to 15,541.32. Nine of the index's main groups retreated.
The energy group was the lone gainer, squeezing out a modest 0.2 percent gain. Canadian Natural Resources Ltd advanced 0.1 percent to C$43.47.
In earnings, newspaper publisher Torstar Corp reported a wider-than-expected loss and shares fell 8.4 percent to C$1.52 .
Declining issues outnumbered advancing ones on the TSX by 187 to 52, for a 3.60-to-1 ratio on the downside.
The index was posting 10 new 52-week highs and 1 new low. (Reporting by Solarina Ho; Editing by Jeffrey Benkoe)