Last week, Bank of Montreal (NYSE: BMO), one of Canada's oldest and largest banks, reported growth in its fiscal fourth-quarter earnings. But it may be the only one that does, as at least two of the Canadian banks scheduled to report fourth-quarter numbers this week have already released preliminary results that warn of lower earnings due to debt write-downs and trading losses.

Analysts surveyed by Thomson Reuters expect Toronto-based Canadian Imperial Bank of Commerce (NYSE: CM) to post earnings 42.6% lower than a year ago, or $1.28 per share. CIBC beat estimates by a penny in the third quarter, but missed by a penny in the period before that. The bank faces a class-action lawsuit related to investments in collateralized debt obligations consisting of U.S. subprime mortgages. Shares have climbed 20.7% from a recent 52-week low of $39.52, but are down 37.8% in the past three months.

Toronto Dominion Bank (NYSE: TD), Bank of Nova Scotia (NYSE: BNS), and Royal Bank of Canada (NYSE: RY) are expected to report more modest earnings declines of $1.01 per share, $0.73 per share, and $0.83 per share, respectively. All three Toronto-based banks topped estimates in the third quarter. Toronto Dominion and RBC have recently announced plans to offer shares in order to raise capital. Toronto Dominion and Scotiabank have been trading near 52-week lows, and their share prices are down around 39% in the past three months. But only Toronto Dominion has a consensus buy recommendation from analysts.