What is the difference between F24 and F29?

F29 is specifically for card-not-present orders the cardmember denies making. F24 is broader unauthorized-use language that can apply in any channel, including when someone known to the cardmember used the card without permission.

Does a CID match guarantee I win an F24 dispute?

No single data point wins it, but a CID and AVS match plus delivery to the verified billing address builds a strong case that the cardmember or their household placed the order.

Can I fight F24 if the customer's family member placed the order?

Yes. Evidence that the order shipped to the cardmember's address and was retained without complaint supports a defense, since Amex expects cardmembers to manage authorized users of their own card.

American Express · Fraud

Reason code F24: No Cardmember Authorization

F24 means the cardmember states they neither made nor authorized the charge, without the dispute fitting a narrower fraud code. It is Amex's general-purpose unauthorized-use claim and shows up in both card-present and card-not-present contexts, including cases where a family member or employee used the card without permission.

Issuer filing window

typically 120 days from the charge date

Merchant response window

typically 20 days to respond

Why F24 chargebacks happen

Stolen card credentials were used to place an order and the true cardmember later spotted the charge.
A relative, partner, or employee with access to the card made the purchase without the cardmember's knowledge.
The cardmember forgot the purchase or did not recognize your billing descriptor and reported it as unauthorized.
An account takeover let a fraudster order through the customer's own stored payment profile.
Friendly fraud: the cardmember received the goods but disputes the charge as unauthorized to avoid paying.

How to fight a F24 chargeback

Assemble evidence linking the cardmember personally to the order: matching name, billing address, email history, and account login records.
Show delivery to the cardmember's verified address with signature confirmation, or usage logs for digital goods tied to their account.
Provide AVS and CID (the four-digit Amex security code) match results from the authorization.
Document any prior undisputed purchases from the same customer profile and card.
Include correspondence where the customer discussed the order, which contradicts a claim of never authorizing it.

How to prevent F24 chargebacks

Verify AVS and CID on every Amex card-not-present transaction and decline hard mismatches.
Run velocity and device-fingerprint screening to catch account takeovers before fulfillment.
Use a clear billing descriptor with a reachable phone number so genuine customers recognize the charge instead of disputing it.
Add SafeKey (Amex's 3-D Secure implementation) on higher-risk orders to strengthen the authentication trail.
Hold and manually review first-time orders that combine high value, rush shipping, and mismatched addresses.

Frequently asked questions

What is the difference between F24 and F29?: F29 is specifically for card-not-present orders the cardmember denies making. F24 is broader unauthorized-use language that can apply in any channel, including when someone known to the cardmember used the card without permission.
Does a CID match guarantee I win an F24 dispute?: No single data point wins it, but a CID and AVS match plus delivery to the verified billing address builds a strong case that the cardmember or their household placed the order.
Can I fight F24 if the customer's family member placed the order?: Yes. Evidence that the order shipped to the cardmember's address and was retained without complaint supports a defense, since Amex expects cardmembers to manage authorized users of their own card.

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