Mobile operators have notched some high profile successes in offering financial services to the poor. Think M-PESA in Kenya or GCash and Smart Money in the Philippines. They’ve have logged several million users for their mobile money transfer services which appear cheaper and more convenient than traditional banking products.

Will banks respond by emulating their new competitors from the mobile world? Banks have an appetite for offering multiple products to their clients, so it would be a boon to the poor if banks wanted to ramp up their offerings via new electronic channels. But the emerging picture is not always rosy.

Many banks see mobile as merely a threat, according to IFC’s Andi Dervishi, who leads investments in alternative-payments systems for the IFC. “Banks remain conservative. They don’t see this as a big opportunity. They are taking a more defensive position, rather than offensive, and not really going after the customer. Their business model needs to be changed.” Countries like India, China, Brazil and Russia now have more mobile phones than ATMs, giving rise to the notion that mobile will support the next wave of innovation in banking in emerging markets where low-revenue customers means banks need to find low-cost channels. But instead of jumping to explore, most banks are playing defense.

One tactic banks use is putting pressure on regulators to slow down mobile operators, or block their services altogether. In Kenya, Vodafone’s local affiliate Safaricom has signed up 2.7 million clients to its M-PESA mobile money transfer service. Banks are clammoring for the central bank to do something. They claim (partially right) it’s unfair for mobile operators to have free rein, with few regulations in place, while they themselves operate under the Banking Act’s detailed rules. The central bank has responded that payment services are a different animal than full-fledged banking, and that rules are coming as soon as Parliament passes the long-awaited National Payment Systems Bill. But that hasn’t stopped banks from putting considerable pressure on their regulators. And so far none of the Kenyan banks have mobile services reaching the unbanked at any scale like M-PESA. I expect we will see a lot more of this in other countries, with banks trying to erect a regulatory wall that keeps new players out of their garden.

Banks which do aim at reaching the poor might take their cue from banks in developed markets. That may not be a good thing. A new report by Mercator’s Retail Banking practice says US banks undermine their own efforts to reach out to the unbanked by levying high fees and other charges. Banks are eager to build relationships with the unbanked and profit from their ATM withdrawals, wire transfers and POS transactions. But they will also try to maximize overdraft revenue gleaned from those customers. Unfortunately, these are the clients hardest hit by accruing fees and overdraft events. Mercator says repeat overdrafters are most often low-income, single, non-white renters. The typical debit card transaction incurs a $34 overdraft fee on a $20 purchase. South Africa’s Competition Commission Banking Inquiry has also found banks charging high fees, to the detriment of consumers, particularly mass market clients, and merchants paying high fees to accept debit card purchases.

Meanwhile, nonbanks are developing some best-of-breed services that threaten to take banks’ customers. Playing defense with regulators won’t stop new nonbank players for long - mobile operators have considerable lobbying power too. And delivering high-priced products may attract some low-income clients, but is unlikely to win their loyalty. If bank managers decide to take a more forward-leaning posture to serving the poor, they may do well to watch a number of their peers (Equity Bank in Kenya, Tameer in Pakistan, WIZZIT in South Africa) who are deep into experiments offering full-fledged retail banking to low-income clients via mobile and cards.