According to this Wall Street Journal article
, the large banks were not that worried about Bank Transfer Day since many of the customers who might switch to a credit union are unprofitable customers. The article mentioned this interesting and questionable statistic:
Moebs Services Inc., a research firm in Lake Bluff, Ill., estimates that it costs the giant banks about $350 to $450 per year to maintain a checking account. In contrast, smaller banks incur costs of $175 to $250 a year per checking account.
I'm not sure if this factors in the effects of the new debit card regulation that caps debit card interchange fees for large banks. One would think that economies of scale would make account servicing costs lower for bigger banks.
Hat tip to reader who emailed me this article.