Mastercard4837Fraud

No Cardholder Authorization

The cardholder says they did not authorize or take part in the transaction. It is Mastercard’s main fraud code and is often used for online and subscription charges.

Why it happens

  • Stolen card details were used online.
  • The cardholder does not recognize the merchant name on the statement.
  • Someone close to the cardholder used the card without permission.

What to send to fight it

  1. Proof of 3-D Secure (Mastercard Identity Check) authentication for the transaction.
  2. Logs linking the cardholder to the purchase: IP address, device, account login, earlier undisputed payments.
  3. Usage or delivery records after the purchase.
  4. Messages with the cardholder about the order.
  5. Proof a refund or reversal was already processed.

How to prevent it

  • Use 3-D Secure for risky payments so the fraud liability moves to the issuer.
  • Use fraud screening and velocity limits at checkout.
  • Use a statement descriptor customers recognize, and send clear receipts.

Summaries written by NoChurn from the networks’ public rules and processor documentation. Networks update their rules and deadlines depend on your processor: check its documentation before you respond.

Other Mastercard codes

← All reason codes
Sources (1)
  1. Mastercard Chargeback Guide, Merchant Edition (19 May 2026) · checked 2026-11-09
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