What American Express F24 means
A fraud chargeback where Amex has concluded you did not show Card Member participation. Causes include mail, phone or internet orders the Card Member did not make, compromised card numbers and lost or stolen cards.
Common causes
- Stolen card details used for an online or phone order
- No usable reply to the earlier fraud inquiry
- Unrecognizable billing descriptor, so a real customer thinks the charge is fraud
Evidence that answers it
- Proof of an offsetting credit (the only response Amex lists)
- For transit contactless only: authorization and account status check evidence within Amex thresholds
How to prevent it
- Answer Amex fraud inquiries (193, 176) fully: charge record, delivery proof with full shipping address, and contracts
- Use a descriptor with your DBA name, website and phone number
- Screen risky orders before fulfilling: AVS, CID, device and IP signals
How Verdikx helps with F24
Verdikx's value on F24 comes earlier: order screening on new Shopify orders scores risk with plain-English reasons before you ship. When an Amex fraud inquiry arrives, the fraud playbook builds the full answer so the case does not reach F24. You review every draft.
Frequently asked questions
What does American Express reason code F24 mean?
Amex F24 means the Card Member denies participating in the charge and you did not provide proof that they did. It usually follows an inquiry you could not answer convincingly. Amex's guide lists only one response: proof that an offsetting credit was already processed, so F24 is rarely reversible once issued.
Is American Express F24 worth fighting?
Our reference rates F24 (No Card Member Authorization) usually one to accept: a response rarely changes the outcome. The evidence that answers it starts with proof of an offsetting credit (the only response Amex lists). The cardholder's bank decides the outcome.
How long does a cardholder have to file a American Express F24 chargeback?
Usually 120 days from the transaction date, under the network's issuer time limits for most codes. Your processor gives you far less time to respond, so work from the due date on the case.
Answer your next F24 with the right evidence.
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Sources
- American Express: How to Manage and Help Prevent Disputes (US reference guide, version 2024PROP) (checked October 5, 2026)
Last reviewed by Verdikx Research.