The country's four largest banks are phasing in new checking account fees for customers who don’t maintain large balances, and large regional banks are expected to follow suit. "Wealthy consumers will be able to avoid these charges by maintaining high balances," said Jeremy T. Rosenblum, a Ballard Spahr partner and consumer finance specialist. "But for the poor and moderate-income people whose balances are lower, it's going to be much harder to avoid these fees."