What Mastercard 4840 means
The cardholder acknowledges one legitimate transaction but disputes additional transactions they say the merchant processed fraudulently using their card details.
Common causes
- Staff reusing a customer's card details for unauthorized charges
- Card data reused for charges outside the original agreement
- Billing errors that look like extra charges
Evidence that answers it
- Separate authorizations and customer approvals for each disputed charge
- Order records and correspondence tying each charge to a request by the cardholder
How to prevent it
- Restrict who can process card-on-file charges and log every charge
- Get written consent for any additional charge
Time limits and caveats
Legacy code. Not listed in the 13 May 2025 Chargeback Guide; acquirer guides map it to 4837 No Cardholder Authorization, whose rules and 120-day time frame then apply. If you see it, confirm the mapping with your processor.
How Verdikx helps with 4840
Verdikx treats 4840 as a fraud-family case under its 4837 playbook and lists every charge on the card for that customer with its authorization, so you can show which charges the customer requested. You review the AI draft before anything is submitted.
Frequently asked questions
What does Mastercard reason code 4840 mean?
Mastercard 4840 Fraudulent Processing of Transactions is a legacy fraud code that no longer appears in the current Chargeback Guide; acquirer documentation maps it to 4837. It meant the cardholder took part in one transaction but the merchant processed extra, unauthorized ones on the same card. Defend with records proving each charge was separately authorized.
Is Mastercard 4840 worth fighting?
Our reference rates 4840 (Fraudulent Processing of Transactions (legacy)) rarely winnable, so check the facts before spending time on a response. The evidence that answers it starts with separate authorizations and customer approvals for each disputed charge. The cardholder's bank decides the outcome.
How long does a cardholder have to file a Mastercard 4840 chargeback?
Usually 120 days from the transaction date, under the network's issuer time limits. Your processor gives you far less time to respond, so work from the due date on the case.
Answer your next 4840 with the right evidence.
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Sources
- Mastercard Chargeback Guide, Merchant Edition (13 May 2025) (checked October 5, 2026)
- Rapyd Acquiring Dispute Operation Guide: Mastercard (legacy code consolidation) (checked October 5, 2026)
Last reviewed by Verdikx Research.