The nation's largest retail banks could lose $92 billion in deposits and $5.1 billion in revenues in the next year, as frustrated customers switch to smaller banks and credit unions.

Customer frustration has fallen in the past two years, but 9.7% of customers at the biggest banks are still likely to move their money to other companies in the next 12 months, according to a study released Thursday by the Connecticut consulting firm cg42. The study measured "bank vulnerability," or the risk of losing customers, by surveying 3,600 customers at the top 10 retail banks between February and March 2013.

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