American Express Chargeback Reason Code
American Express Reason Code C18: Guaranteed Reservations
Category Consumer DisputesBy Payment Defender Editorial TeamUpdated July 17, 2026Last reviewed July 17, 2026
What American Express Reason Code C18 Means
American Express reason code C18 applies to disputes involving guaranteed reservations, such as a no-show charge the Cardmember believes was applied incorrectly. It commonly arises in lodging and similar reservation-based industries.
Why This Chargeback Happens
This dispute commonly occurs when a Cardmember cancelled a guaranteed reservation within the allowed window but was still charged a no-show fee, when cancellation policies are unclear, or when a reservation was honored differently than expected.
What the Cardholder or Issuer Is Claiming
The Cardmember is claiming a guaranteed-reservation charge, such as a no-show fee, was applied incorrectly or after a valid cancellation.
What Merchants Should Review
Review the reservation record, cancellation policy, and any cancellation confirmation. Confirm whether the Cardmember cancelled within the allowed window and whether the no-show charge complied with your disclosed terms.
Recommended Chargeback Evidence
- Reservation confirmation with disclosed cancellation terms
- Records of any cancellation request and its timing
- Proof the guaranteed-reservation policy was communicated
- Documentation supporting a valid no-show charge, if applicable
How to Prevent Similar Disputes
Merchants may reduce these disputes by clearly disclosing reservation and cancellation terms, confirming cancellations promptly, and applying no-show charges only when policies were met. Providing cancellation numbers helps document compliance.
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.