Standard & Poor’s Ratings Services on Tuesday lowered its long-term ratings on RBC Centura Banks Inc., but it didn’t touch the ratings of parent company RBC Financial Group.

S&P lowered the rating on RBC Centura and its subsidiaries, including the bank’s long-term counterparty credit rating. The ratings are removed from CreditWatch, on which they were placed on June 18. The outlook is now stable.

The rating agency says that the action reflects the bank’s recent poor earnings performance, which weakened RBC Centura’s stand-alone financial profile. “The profitability deterioration is a function of operational disruptions at RBC Centura’s mortgage subsidiary, RBC Mortgage, which RBC repositioned as a subsidiary of RBC Centura Bank in 2003 as part of an ongoing restructuring that realigns RBC Centura’s business and risk profile,” it says.

“Mortgage company operational disruptions, which included backlogs in the mortgage warehouse and losses on fraudulently originated loans, effectively erased three quarters worth of earnings at the RBC Centura Banks Inc. level,” S&P says.

Mortgages aren’t S&P’s only worry. “While the largest losses related to mortgage banking activities, fundamental changes in RBC Centura’s business mix and risk profile are further pressuring profitability levels,” it says. “As a member of the larger Royal Bank of Canada organization, certain fee-based businesses have been transferred to other U.S. subsidiaries of the Canadian parent, and the investment portfolio has been repositioned to reduce interest rate risk. While these changes lower the interest rate risk profile, the U.S.-based banking unit’s earnings power is nevertheless significantly diminished.”

The stable outlook reflects S&P’s expectation that RBC Centura’s profitability should gradually improve, but it may not fall in line with that of its peers. “From a longer-term perspective, RBC Centura’s rating is ultimately a function of Royal Bank of Canada’s continued interest in the U.S. banking market,” S&P says.

“In light of its prominent position as the flagship of Royal Bank’s U.S.-based retail and commercial banking expansion, Standard & Poor’s views RBC Centura as a strategically important subsidiary of its Canadian parent. While Royal Bank’s recent managerial support of RBC Mortgage confirms the current importance of the U.S. subsidiary to the Canadian parent, Standard & Poor’s expects that RBC Centura’s long-term significance to its parent will ultimately be a function of the success of the U.S. expansion strategy, which is yet to be determined.”