TORONTO, May 20 (Reuters) - Canada's main stock index ended lower on Wednesday, snapping a three-day winning streak, as banks led a broad retreat offset by gains in oil and gas shares.
The Toronto Stock Exchange's S&P/TSX composite index unofficially closed down 48.19 points, or 0.32 percent, at 15,072.83. Nine of the 10 main sectors fell. (Reporting by Alastair Sharp. Editing by Andre Grenon)