Reason code

American Express reason code F31 is used when a transaction was completed using a lost, stolen, or non-received card, and the merchant’s terminal was not EMV chip-enabled. Under the EMV liability shift, merchants who don’t use chip-capable technology may be liable for fraud tied to unauthorized card use.

This reason code typically applies to in-person transactions where a magnetic stripe was swiped instead of using the EMV chip. If the card was flagged as compromised and the chip wasn’t used for verification, the chargeback liability can shift to the merchant.

‍

If the transaction was properly authorized or the terminal was EMV-capable, submit documentation to support your case:

• Provide terminal logs showing chip-read attempts or fallback authorization

• Include signed receipts or security footage if available

Protect your business from liability by upgrading to EMV chip-compliant terminals:

• Ensure all devices support chip reading and avoid unnecessary fallback to magnetic stripe

• Train staff to follow EMV procedures and verify customer identity when needed