The allegations illustrate the challenge facing banks and credit-card processors already under heightened pressure to detect suspicious transactions and thwart money laundering.
MasterCard and Target are in talks about a settlement in which the retailer would pay banks about $20 million for costs they incurred in its 2013 data breach.
Endurance Specialty Holdings Ltd., the Bermuda-based provider of property and casualty insurance, announced a $3.2 billion offer to buy Aspen Insurance Holdings Ltd. after the target company turned down its proposal.