Plaintiffs accused Chase and more than 30 other banks of processing customers' debit card transactions in a way to wrongfully maximize overdraft fees. Specifically, the banks processed debit card transactions not in the order in which customers conducted them but instead from the highest-to-lowest transaction balances; the change allegedly caused customers to drain their accounts quickly and maximized the overdraft fees assessed against them.
 
"Chase made enormous profits from overdraft charges, much of it taken from Chase's most vulnerable customers," the class action claims. The bank generated $500 million a year in post-tax income from high-to-low re-sequencing, according to Chase's own analysis.
 
As cover for its actions, plaintiffs allege, Chase falsely maintained that it had chosen high-to-low processing because consumers requested it.