The 05: Do Not Honor card declined response is the most common and general ‘decline’ message for transactions that are blocked by the bank that issued the card. This week Finance Monthly hears from Chris Laumans, Adyen Product Owner, on the complexities of this mysterious and vague transaction response.

05: Do Not Honor may be the largest frustration for any merchant that regularly analyses their transactions. Although it frequently accounts for the majority of refusals, it is also the vaguest reason, leaving merchants and their customers at a loss about how to act in response.

Although unfortunately there isn’t an easy, single answer about what this refusal reason means, there are several suggestions as to what could be the cause behind the non-descript message. So what might the 05: Do Not Honor mean? From our experiences analysing authorisation rates and working with issuers and schemes, here are some plausible explanations.

Insufficient funds in disguise

In probably half of the cases, 05: Do Not Honor is likely just an Insufficient Fund refusal in disguise. Reality is that some issuers (or their processors) do a poor job of returning the appropriate refusal reasons back to the merchants. This is both due to the use of legacy systems at the issuer side as well there being no mandates or monitoring by the schemes on this, letting issuers continue to use it as a blanket term.

By looking at the data from various banks, it is easy to see how “Do Not Honor” and Insufficient Funds can often be used interchangeably. Records that show a disproportionately high level of Do Not Honor and a low level of Insufficient Fund refusals would suggest one masquerading as the other. Given that Insufficient Funds is one of the most common refusal reasons, 2nd maybe only to “Do Not Honor”, it makes sense that “Do Not Honor” by some banks may actually represent Insufficient Funds.

Refusal due to credential mismatches

Although the words “Do Not Honor” aren’t the most revealing, sometimes other data points in the payment response can be clues for the refusal. Obvious things to look at are the CVC response, card expiry date, and, to a lesser extent, the AVS response. For lack of a better reason, issuers will frequently default to using “05: Do Not Honor” as the catch-all bucket for other denials.

Suspicion of fraud

The most appropriate use of “05: Do Not Honor” would be for declining transactions due to suspicious activity on the card. In some cases, although the card is in good standing and has not been reported lost or stolen, an issuer might choose to err on the side of caution due to a combination of characteristics on a given transaction. For example, a high value transaction made at 3am from a foreign based merchant without any extra authentication, likely will trigger a few too many risk checks on the issuer side. These types of refusals will again unfortunately be designated into the “05: Do Not Honor” category, with merchants drawing the short straw. Even though issuers may be able to point to specific reasons why the transaction was refused, issuers have no way to communicate this back to the merchant.

Some astute merchants might point out that issuers should be able to use “59: Suspected fraud” in these cases. Some issuers however remap these 59 refusal reasons to 05 before sending the response to the acquirer to protect store owners in the POS environment and avoid uncomfortable situations with the shopper standing in front of them.

Collateral damage

Finally, the reality is that your likely not the only merchant that a given shopper interacts with. Regardless of how good your business is or how clean your traffic is, a shopper’s recent history with other merchants will influence the issuers decision on your transaction. For lack of a better reason, the catch-all 05: Do Not Honor refusal in some cases be seen as “Collateral damage”. If the shopper coincidentally just made a large purchase on a high-risk website or went on a shopping spree before reaching your store, there is the possibility that the issuer may decline the transaction at that moment in time. In these cases, there is unfortunately very little that can be done, except to ask for another card or to try again later.

Hopefully this helps shed some light on the possible reasons why ‘05: Do Not Honor’ is so dominant in the payment space and that there is no single reason for this response. Adyen’s advice to dealing with these refusals is to look at the data at individual issuer/BIN levels and from there, try to distil patterns particular to those bank’s shoppers.