The PCI Standard is mandated by the card brands and administered by the Payment Card Industry Security Standards Council. The standard was created to increase controls around cardholder data to reduce credit card fraud. Validation of compliance is performed annually, either by an external Qualified Security Assessor (QSA) or by a firm specific Internal Security Assessor that creates a Report on Compliance for organizations handling large volumes of transactions, or by Self - Assessment Questionnaire (SAQ) for companies handling smaller volumes.
who is responsible for ensuring merchant compliance with pci dss
Payment Card Industry Security Standards Council