PCI DSS Compliance Validation for Merchants

Level 1
AMEX : Annual on-site review by QSA (or internal internal auditor if signed by officer or merchant company) Quarterly scan by ASV
MASTERCARD : Annual on-site review by QSA Quarterly scan by ASV
VISA : Annual on-site review by QSA (or internal auditor if signed by officer of merchant company) Quarterly scan by ASV)

Level 2
AMEX : Quarterly scan Quarterly scan by ASV by ASV
MASTERCARD : Annual Self-assessment Questionnaire Quarterly scan by ASV
VISA : Annual SAQ Quarterly scan by ASV

Level 3
AMEX : Quarterly scan by ASV (recommended)
MASTERCARD : Annual SAQ Quarterly scan by ASV
VISA : Annual SAQ Quarterly scan by ASV

Level 4
AMEX : N/A
MASTERCARD : Annual SAQ (recommended) Quarterly scan by ASV (recommended)
VISA : Annual SAQ (recommended) Quarterly scan by ASV (recommended)