Great question! With Yoco, all transactions are online and monitored. This means that every transaction is checked with the issuing bank (your customers bank) and their bank has to approve the transaction.
All Yoco card readers are Chip and PIN enabled. Chip and PIN cards have much lower fraud activity on them and are being rolled out globally as the standard for bank cards.
All banks keep a hot card list that keeps all cards that have been reported as lost or stolen. In Yoco's case, this list is kept by our partner bank, Mercantile Bank, who screen every transaction against the hot card list. Once a card is flagged, our Risk team starts an investigation with our partners in order to confirm if it is indeed fraudulent activity.