Why B of A really killed the debit card fee

This post comes from Seth Fiegerman at partner site The Street.

When Bank of America announced last week it would nix its proposed $5 monthly debit card fee, the official explanation given was that the company was responding to the "concerns" of its customers, but that may be putting it too lightly.

In reality, it may be due more to the bank's concerns that it wouldn't have nearly as many customers if the fee went into effect.

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At least 650,000 consumers have joined credit unions since Sept. 29, when Bank of America announced it would introduce a debit card fee in the coming months, according to a report released Thursday by the Credit Union National Association, which is based on surveys of 5,000 credit unions nationwide.

While the survey doesn't show which companies the new credit union customers banked with before, the survey did find that four in every five credit unions that experienced a surge in members attributed it to the blowback from fees being considered by big banks such as Bank of America.

At the same time, it's worth noting that this survey doesn't factor in the number of consumers making a last-minute switch as part of Bank Transfer Day, the massive social media-driven movement that was urging consumers to close their accounts with the big banks before Saturday.

While the full effect of Bank Transfer Day won't be known for days or even weeks, media reports from across the country showed thousands were out over the weekend to make their point to the big banks. Even The Wall Street Journal, which snarked that "people who gravitate to credit unions tend to be unprofitable for giant banks because of the small balances they keep on deposit," acknowledged the numbers involved -- anecdotally:

"On Saturday, the Boeing Employees' Credit Union in Seattle signed up a one-day record 659 new members. At the grand opening of a Randolph-Brooks Federal Credit Union branch in Pflugerville, Texas, the parking lot was so full that customers had to leave their cars across the street."

The Journal's headline? "Credit unions poach clients."

After years of being able to increase fees with little fear that customers would jump ship, the big banks finally had a reason to cave to consumer demands, perhaps most of all for Bank of America.

One survey released last week before Bank of America killed off its debit card fee found that only 40% of the bank's customers planned to keep it as their primary bank going forward. The survey also found that just over a quarter of Bank of America's customers were satisfied with the bank overall. The findings were the lowest by far of any major bank.

Given this reality, going through with the $5 fee could easily have been the final straw for many customers.

More on The Street and MSN Money:

• How Bank of America can win back customers
• Bank Transfer Day: How everyone wins
• How big corporations exploit tax loopholes
• Banks' take from debit fees? $875M a month
• Bank customers win one -- for now
• Today's best savings rates