Disaffected mass-affluent customers, defined as those with $100,000 in assets or more, were much more penalizing toward the offending institution than mass-market customers, according to the survey. As measured by the size of the relationship with the bank, mass-affluent customers are about twice as punitive in their reaction to a negative event with their institution. Such behavior is tremendously disconcerting for offending institutions, McKinsey notes, since mass-affluent customers produce 13 times as much profit as mass-market clients.

I haven’t seen anything to confirm this, but I’d bet the mass-affluent in the United States view themselves as particularly time-constrained relative to other groups. Spending the time necessary to resolve a problem like a bank mistake, therefore, is particularly resented by this demographic. They are much more likely, therefore, to view problem events as a reason to change institutions.

While this particular study didn’t draw the connection, these results seem a clear explanation for the explosion in both the numbers and profitability of service-oriented community banks in recent years. It is also a telling explanation of why it is so difficult for an acquisition-happy regional bank, by definition constantly battling merger execution and integration risk, to maintain profitability in their acquired properties.