Código de motivo 4870 de MasterCard: devolución por transferencia de responsabilidad relacionada con el chip — Guía para comerciantes

Mastercard reason code 4870, the Chip Liability Shift chargeback, is filed when a cardholder disputes a counterfeit or fraudulent transaction and the merchant did not process it through EMV chip technology as required. Under Mastercard's EMV Liability Shift, effective October 2015, whichever party (issuer or merchant) failed to support chip processing absorbs the fraud loss, and in most 4870 cases that is the merchant.

Sources: Mastercard Chargeback Guide, EMVCo Worldwide EMV Deployment Statistics.

What Is the Chip Liability Shift?

The Chip Liability Shift is the rule set that reassigns who pays for a counterfeit-card transaction based on whether both parties supported EMV chip processing. Before the shift, issuing banks generally absorbed counterfeit fraud losses on magnetic-stripe transactions.

With EMV chip technology, that liability moves to whichever party did not support chip processing. EMV stands for Europay, Mastercard, and Visa, the networks that jointly developed the standard. Each chip generates a unique cryptogram for every transaction, which is what makes cloned magnetic-stripe fraud far harder to pull off on a properly processed chip-enabled card.

Mastercard's Chip Liability Shift took effect in October 2015. If a merchant accepts a counterfeit chip card on a non-EMV-compliant terminal, or fails to read the chip correctly, the merchant becomes liable for the fraud loss, the disputed goods or services, any chargeback fee, and potential compliance penalties for repeat cases.

Mastercard Reason Code 4870 Explained

When Is Mastercard Reason Code 4870 Applied?

Issuers file reason code 4870 when a cardholder reports a counterfeit or unauthorized transaction and Mastercard's records show the merchant's terminal did not properly capture EMV chip data for that sale. For how it compares with codes on other networks, see our guide to chargeback reason codes.

What Happens If a Merchant Loses a Reason Code 4870 Chargeback?

A lost 4870 chargeback means the merchant forfeits the transaction funds, absorbs any chargeback fee, and keeps the count against its chargeback ratio. A pattern of 4870 losses can also trigger a closer look under Mastercard's merchant monitoring process, the Mastercard GMAP.

Mastercard Reason Code 4870 Time Limits and Required Evidence

Reason code 4870 follows Mastercard's standard chargeback clock, not a shortened one, but merchants routinely lose these disputes simply by missing a step in that clock.

To fight a 4870 chargeback, Mastercard expects at least one of the following in the second presentment: proof the transaction was correctly processed as an EMV chip read (the terminal's DE 55 chip data), evidence the card presented did not actually carry an EMV chip, documentation that the cardholder authorized and received the purchase, or written confirmation from the cardholder withdrawing the dispute.

Common Causes of Mastercard Reason Code 4870 Chargebacks

Failure to Use EMV-Compliant Equipment

Terminals that only support magnetic-stripe swipes cannot capture the chip data Mastercard requires, so any counterfeit-card sale run through them lands on the merchant by default.

Misuse of EMV Technology

Swiping a chip-enabled card instead of inserting it, or skipping the PIN or signature prompt, can produce the same fallback-transaction outcome as not having EMV equipment at all. Chargeflow's Mastercard chargeback guide breaks down how this and other reason codes get filed, which is why staff training matters as much as the hardware itself.

Incorrect Processing Procedures

Authorizing a sale the cardholder never approved, or mishandling a refund, can also surface as a 4870 dispute even when the terminal itself worked correctly.

Why EMV Adoption Has Not Eliminated Reason Code 4870

Chip technology is nearly universal today. EMVCo puts global EMV chip usage at 97% of card-present transactions as of Q4 2025, yet 4870 chargebacks persist. Research from the Federal Reserve Bank of Kansas City helps explain why: on dual-message networks like Mastercard, card-present fraud rates actually rose from 10.1 to 14.9 basis points between 2017 and 2021, because the US rollout paired chip cards with signature or no-verification checkout rather than the PIN requirement used in most other EMV markets.

In practice this means most 4870 cases today trace back to a processing gap, a fallback swipe, a misread chip, a skipped verification step, rather than the outright absence of chip hardware.

How to Prevent Mastercard Reason Code 4870 Chargebacks

Use EMV-Compliant Equipment Correctly

Confirm every terminal reads chip cards by insertion, not swipe, and that software is current enough to capture full DE 55 chip data on each sale.

Train Staff on Proper Processing

Employees need to know how to prompt for chip insertion, handle a genuine fallback correctly, and never override a chip read with a manual swipe to save a few seconds at checkout.

Verify Cardholder Identification

Checking ID against the name on the card adds a second layer of defense and gives you stronger evidence against fraud claims if a dispute is filed anyway.

Catch Disputes Before They Escalate

Address customer complaints immediately so they get resolved as refunds instead of escalating to chargebacks, and use real-time chargeback alerts to flag a disputed transaction while there is still time to intervene or refund before it becomes a formal 4870 case.

Responding to a Mastercard Reason Code 4870 Chargeback

Merchants have 45 days from the chargeback date to submit a second presentment, not the shorter window often assumed, but that time goes fast once documentation needs to be pulled together.

Gather the Right Evidence

Pull the terminal's chip-read data (DE 55), the receipt, shipping or delivery confirmation, and any prior correspondence with the cardholder about the same purchase.

Build the Rebuttal

State plainly why the chargeback does not meet Mastercard's criteria for reason code 4870, cite the specific evidence that proves it (a valid chip read, cardholder authorization, an existing refund), and attach the supporting documents.

Submit Within 45 Days

File the second presentment through your acquirer inside that 45-day window. A late submission forfeits the case automatically, regardless of how strong the evidence is.

Mastercard Reason Code 4870 FAQ

What is EMV liability shift?

EMV liability shift is the card network rule, in effect since October 2015 for Mastercard, that moves responsibility for counterfeit-card fraud to whichever party, the issuing bank or the merchant, did not support EMV chip processing for that transaction.

Who is liable when a chip card is swiped instead of inserted?

If a merchant swipes a chip-enabled card's magnetic stripe instead of reading the chip, and the transaction turns out to be fraudulent, the merchant typically absorbs the loss under the EMV Liability Shift, since the chip capability was available but not used.

Close the Gap Between EMV Compliance and Chip Liability Shift Chargebacks

Reason code 4870 rarely comes down to missing chip hardware anymore. It comes down to a swipe instead of an insert, a skipped verification step, or evidence that never made it into the second presentment inside the 45-day window. Confirm your terminals capture full chip data on every sale, train staff to never fall back to a swipe by default, and treat the response clock as non-negotiable once a 4870 dispute lands.