Higher funding costs, potential regulatory capital weaknesses and rising risks tied to commercial real estate loans amid weakening demand for office space were the triple whammy of factors that prompted Moody's to lower credit ratings for 10 small and midsize US banks; and noted in a slew of notes that it may downgrade major lenders.

"Collectively, these three developments have lowered the credit profile of a number of US banks, though not all banks equally," the ratings agency wrote in some of the assessments.

Firms that had ratings cut included M&T Bank Corp., Webster Financial Corp., BOK Financial Corp., Old National Bancorp, Pinnacle Financial Partners Inc., and Fulton Financial Corp.