IMF (Australia) executives and their lawyers at Maurice Blackburn are wrestling with the tricky question of when to extend the legal action being brought against ANZ over its exception fees to other major banks.While IMF Australia executive James Middleweek willingly told Banking Day on Friday that the firm was looking at funding other class actions he refused to comment on when these might be initiated."Clearly, other cases are being contemplated," he said. "I can't say anything more than that."IMF is funding the ANZ case after signing up more than 34,000 customers who have been forced to pay exception fees to the bank since 2004.Around 240,000 people altogether have registered as claimants through Financial Redress, a subsidiary company of IMF. The firm recruited most of these claimants in the middle of 2010.The problem for IMF, and the more than 200,000 customers at banks other than ANZ who are aggrieved about late fees on credit cards or dishonour fees on transaction accounts, is that the financial incentive for claims to be brought against the likes of Commonwealth Bank, Westpac and NAB is diminishing by the day.Most civil claims for breach of contract are usually subject to a six-year limitation period.Because the major banks and second-tier players slashed most of their exception fees by an average of 50 per cent in the second half of 2009, and abolished them altogether for some account holders, the value of any future litigation has been reducing for around 18 months.According to data published by the Australian Bankers Association, the industry collected A$764 million in exception fees in 2010, which was down $717 million on the 2009 take of $1.48 billion.The ABA data shows that exception fee revenue fell sharply across all product categories last year, with the reductions being spread equally between retail and business customers.Banks such as Westpac and CBA are now better placed to argue that the revised fee regime closely reflects the cost of managing overdraws and late payments, and, therefore, cannot be characterised as "gouging".While such arguments would make these banks vulnerable to claims before 2010, the limitation period means that only four to five years of excessive pricing on exception fees can now be claimed by future litigants.The industry is watching closely for the next development in the ANZ case, especially if the judge in the case, Michelle Gordon, decides that the plaintiffs can advance their claim in the Federal Court on the basis of equity law principles.If Justice Gordon decides that equity principles do not apply, the plaintiffs will then have to consider the prospect of mounting an action under the unconscionable conduct provisions of the Competition and Consumer Act. Such an outcome would lead to further delays and would require IMF to stump up additional cash to support what would be a more fact-intensive and time-consuming case.The main obstacle to initiating claims against other banks appears to be one of cost.The ANZ case is the first significant class action brought against an Australian bank for breach of contract. All