Collapsed payments processor Wirecard miscoded gambling transactions and had high levels of stolen card purchases and reversed transactions, leading to hefty fines from card networks Visa and Mastercard, according to people familiar with the matter.

Visa and Mastercard each imposed fines exceeding $10m more than a decade ago, and the networks remained wary of Wirecard’s business. Since at least 2015, Visa executives were concerned that Wirecard was a problem, according to some of the people familiar with the matter.