One of the largest merchants operating the whole world will have less than two years to secure credit card transactions, Visa have been announced on Monday.

Level-one retailers -- those processing more than six million Visa transactions per year -- must prove adherence to the Payment Card Industry Data Security Standard (PCI DSS) by Sept. 30, 2010, Visa said in a news release. After that date, Visa may begin issuing fines to acquiring banks, which typically pass the penalties down to the merchants.