American Express Chargeback Reason Code
American Express Reason Code P01: Unassigned Card Account
Category Processing ErrorsBy Payment Defender Editorial TeamUpdated July 17, 2026Last reviewed July 17, 2026
What American Express Reason Code P01 Means
American Express reason code P01 applies when a charge was submitted to a Card account number that is not assigned or does not exist. The dispute results from a charge tied to an invalid or unassigned account.
Why This Chargeback Happens
This dispute commonly occurs when a Card number is keyed incorrectly, when a transaction references an outdated or invalid account, or when data-entry errors create a charge to an unassigned number.
What the Cardholder or Issuer Is Claiming
American Express is asserting that the charge was submitted to an unassigned or invalid Card account.
What Merchants Should Review
Review the Card number submitted, authorization data, and the source of the account information. Confirm whether the number was entered correctly and matches a valid account.
Recommended Chargeback Evidence
- Authorization records showing the account number used
- Proof the correct Card number was captured at purchase
- Transaction data identifying the source of the account number
- Documentation of any correction to the account number
How to Prevent Similar Disputes
Merchants may reduce these disputes by validating Card numbers at entry, using electronic capture instead of manual keying, and correcting data-entry errors before submission. Accurate account capture helps prevent unassigned-account charges.
Important Limitations
This page is educational and reflects common industry usage. American Express dispute rules, timelines, and evidence requirements change over time and vary by market and program. Merchants should confirm current requirements with American Express or their processor before responding to any dispute.
Related Reason Codes
Sources and Review Information
- American Express: American Express Merchant Regulations – U.S.
Last reviewed July 17, 2026
Chargeback rules, evidence requirements, and response options may vary by card network, region, processor, and dispute circumstances.