"Things that we're particularly watching are the quality of the loan portfolios for the banks," said Tom Kersting, a financial services analyst with brokerage Edward Jones.

In particular, analysts will be closely monitoring credit quality at CIBC, which is the country's largest credit-card operator. In June, CEO Gerald McCaughey said retail credit is the bank's "primary challenge" because "consumer loan losses remain higher than we would like."

"The slowdown appears broad-based in nature -- we estimate sequentially weaker results for debt and equity underwriting revenues, mergers and acquisition advisory fees, wealth management revenues and flat to down trading revenues."