Mastercard Chargeback Reason Code
Mastercard Reason Code 4870: Chip Liability Shift
Category FraudBy Payment Defender Editorial TeamUpdated July 17, 2026Last reviewed July 17, 2026
Applicable EMV transactions
What Mastercard Reason Code 4870 Means
Mastercard reason code 4870 applies the EMV chip liability shift, used when a fraudulent transaction occurred on a chip-capable card at a terminal that did not properly process the chip.
Why This Chargeback Happens
This dispute commonly occurs when a counterfeit or fraudulent card is used at a terminal that fell back to magnetic stripe or otherwise failed to complete a chip transaction, shifting liability to the party that did not support EMV.
What the Cardholder or Issuer Is Claiming
The issuer is asserting that fraud occurred on a chip card at a non-compliant or improperly processed terminal, shifting liability to the merchant.
What Merchants Should Review
Review the terminal's EMV capability, the transaction entry mode, whether a chip fallback occurred, and the authorization and authentication data for the disputed sale.
Recommended Chargeback Evidence
- Records showing the terminal processed the chip successfully
- Transaction entry-mode data confirming EMV was used
- Authorization data documenting the chip transaction
- Evidence the terminal was EMV-compliant at the time of sale
How to Prevent Similar Disputes
Chip liability disputes may be reduced by using EMV-compliant terminals, avoiding magnetic-stripe fallback where possible, keeping terminal software current, and ensuring chip cards are dipped rather than swiped.
Important Limitations
This page is educational and reflects common industry usage. Mastercard EMV liability rules apply only to applicable chip transactions and change over time. Merchants should confirm current requirements with their acquirer or processor before responding to any dispute.
Relevant Payment Defender Products
AlertBridge™
AlertBridge™ may help merchants intercept fraud disputes as alerts before they become chargebacks.
Explore AlertBridge™
Related Reason Codes
Sources and Review Information
- Mastercard: Mastercard Chargeback Guide
Last reviewed July 17, 2026
Chargeback rules, evidence requirements, and response options may vary by card network, region, processor, and dispute circumstances.