(Yicai) Sept. 15 -- Shanghai Pudong Development Bank and Mastercard are investigating a string of unauthorized overseas transactions affecting holders of their World series credit cards, saying customers will not be made to bear any fraudulent charges.

SPD Bank and Mastercard NetsUnion Information Technology Beijing have promptly activated the emergency response system, contained the risk, and pledged to protect affected clients from financial losses, the pair announced in separate statements yesterday.

Mastercard NetsUnion is Mastercard's joint venture in China with NetsUnion Clearing. It is mainly responsible for the clearing services of Mastercard-branded bank cards in the Chinese mainland.

A number of SPD Bank Mastercard World Premium and World Elite cardholders recently said on social media that their cards had been used for many fraudulent overseas payments. Most of these transactions occurred without their knowledge or consent.

Credit card fraud is not uncommon, but this case is notable because it targets holders of premium cards and involves relatively large sums. These cards, co-issued by SPD Bank and Mastercard under the World card series, cater to frequent travelers and heavy cross-border spenders.

The amounts involved range from several thousand to tens of thousands of Chinese yuan, equal to a few thousand to several thousands of US dollars, Yicai learned from the social media posts. Many victims said they had not used the card on suspicious websites, had not made any overseas offline purchases, and had not shares their personal information.

One cardholder said he was in New Zealand when he received a notification of a charge in Brazilian real and was fraudulently charged nearly CNY20,000 (USD2,810) within three days.

If the same card product is the subject of concentrated overseas fraud over a short span of time, the root cause could be a hacker attack or an information leak somewhere in the payment chain, an industry insider told Yicai.

Under international credit card clearing rules, if the fraud is not caused by the cardholder’s negligence, the ultimate loss usually falls to the issuing bank or the card network. The insider said banks typically advance the stolen funds first, then seek recovery through the card networks or insurance companies.

Editors: Tang Shihua, Futura Costaglione