TORONTO -- A plethora of negative corporate and earnings news weighed on the Toronto stock index Thursday, with banks and energy companies making up the biggest portion of the retreat.

The S&P/TSX composite index gave up 82.66 points to 15,550.55, as the majority of sectors finished the day in the red.

Moody's Investors Service downgraded Canada's six big banks over concerns about ballooning consumer debt and inflated housing prices.

The move resulted in a decline across Canadian banks, with Royal Bank (TSX:RY) losing 0.62 per cent to $92.75, CIBC (TSX:CM) falling 1.26 per cent to $94.48, and TD Bank (TSX:TD) dropping 0.74 per cent to $63.42 a share.

"Moody's looks at this on a periodic basis. The reality is that private sector debt is getting higher and higher in Canada and the consumer is more indebted," said John Stephenson, president and CEO at Stephenson & Co. Capital Management.

"There are worries that Canada could be in a situation similar to what happened in the U.S. I think there is scant chance of that. Nonetheless that's on the mind of the ratings agencies."

Elsewhere, shares in Aimia Inc. (TSX:AIM) fell $5.60, or 62.71 per cent, to $3.33 after the country's largest airline, Air Canada (TSX:AC), announced it was not renewing its contract with the loyalty points company and was instead starting its own in-house program.

One bright spot was plane and train maker Bombardier Inc. (TSX:BBD.B), which saw its stock rally after Pierre Beaudoin, the scion of the family that controls the company, announced he was stepping down as executive chairman after he became a focal point of public protests and shareholder frustration. Its shares rose 7.8 per cent, or 16 cents, to $2.21.

On Wall Street, indices were lower amid a round of dismal earnings from retailers Macy's and Kohl's.

The Dow Jones industrial average lost 23.69 points to 20,919.42, the S&P 500 index shed 5.19 points to 2,394.44, and the Nasdaq composite index was down 13.18 points to 6,115.96.

"It was looking like a pretty good earnings season south of the border," said Stephenson, noting that the disappointing results raise the question about why consumers aren't shopping in an economy that shows signs of strength.

The Canadian dollar dipped 0.18 of a U.S. cent to an average value of 72.96 cents US.

In commodities, the June crude contract was up 50 cents at US$47.83 per barrel and the June natural gas contract was up eight cents at US$3.38 per mmBTU.

The June gold contract gained $5.30 at US$1,224.20 an ounce and the July copper contract was up a penny at US$2.51 a pound.