Around 800 Bank of Bermuda customers have had their cards compromised after a security breach in the US.
It comes less than a year after 1,600 of the bank.s customers were hit when a hacker broke into a system - again in America.
Richard Brown, head of personal financial services, said: "Bank of Bermuda received notification from Visa that as a result of a recent breach of security associated with a processor of ATM transactions in the United States, a number of Bermuda-based credit and debit card numbers had been exposed to possible fraud."
He said the Bank was working to safeguard customers by closing the compromised accounts immediately, contacting affected clients and issuing replacement cards.
He added: "Approximately 800 Bank of Bermuda cards have been affected. We remind our clients to review their statements vigilantly for fraudulent transactions and to contact us immediately if they detect anything suspicious."
Some customers said they weren't contacted. Bermudian blogger Sean Soares wrote on his website on Friday that he had tried to use his Bank of Bermuda debit card but had it declined several times, including when he was treating a client to dinner.
It led him to transfer more money in and take money out at an ATM, only for the card to be declined again when he tried to pay for a lunch with it.
"Again, quite embarrassing, although now I was annoyed. Upon getting back from lunch I immediately contacted the bank and asked them what in the hell was going on.
"Apparently 900 debit cards numbers were stolen, from where I don't know.
"So the bank put a stop on these cards, meaning that you can use them in an ATM machine, however once you attempt to purchase something with them, they are immediately declined without any reason.
"While I appreciate the bank for looking after my card.s well being, they could have at least tried to get in touch with me to explain what was going on. Heaven forbid if I was away! A quick call could have saved me a lot of embarrassment."
However the Bank said not all customers had left up-to-date contact information.
Asked why a general media alert had not been put out, the Bank said it was not necessary as only certain customers were affected.
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