CANADA STOCKS-TSX falls as Moody's downgrades banks, Aimia plunges

TORONTO, May 11 (Reuters) - Canada's main stock index fell on Thursday, as a Moody's downgrade of Canadian banks struck financials, and frequent-flyer points operator Aimia Inc plunged on news its program would be dropped by the country's largest airline.

The Toronto Stock Exchange's S&P/TSX composite index unofficially closed down 82.66 points, or 0.5 percent, at 15,550.55. Eight of the index's 10 main groups ended lower. (Reporting by Fergal Smith; Editing by James Dalgleish)