Simultaneous rating actions by Moody's Investors Service and Fitch Ratings on Canadian banks do not reflect a difference of opinion but rather a difference in rating levels. On Monday, Moody's downgraded the long-term ratings of six Canadian banks, concluding a review initiated last October. The downgrades reflect Moody's concern over the banks' exposure to increasingly indebted Canadian consumers and elevated house prices.Included in the downgrades were Bank of Nova Scotia, to Aa2 from Aa1, and Canadian Imperial Bank of Commerce, to Aa3 from Aa2. All ratings outlooks are stable.Bank of Nova Scotia has A$1.0 billion of January 2014 covered bonds on issue in the domestic market and CIBC has A$600 million of January, 2015 and March 2016 covered bonds on issue. The ratings on the covered bonds are unaffected.At the same time, Fitch affirmed the ratings on six Canadian banks, including Bank of Nova Scotia and Canadian Imperial Bank of Commerce, after completing an industry peer review.The affirmed the long term rating on both banks is AA-, which equates to a Aa3 rating from Moody's. The affirmation comes despite Fitch's recognition of continued risk with respect to the Canadian residential housing market, increasing consumer debt levels, global economic headwinds, slowing loan growth, margin compression and heightened competition.