USPS Nixie Mail Codes
Mail can be returned and marked with USPS nixie mail codes if it is missing NCOA forwarding information or secondary address information. This is why it is important to validate addresses before mailing.
Missing forwarding information
When someone moves they can submit forwarding information via a change of address form to the USPS. If this information was never submitted by the resident, the mail will likely be returned marked "Not Deliverable as Addressed Unable to Forward". TrueNCOA verifies that addresses are valid and deliverable and provides any 18 and 48 month address updates.
Missing secondary information
Another common reason for returned mail is missing or invalid secondary information such as apartment or suite number. TrueNCOA returns status codes from the validation process to help you determine why primary or secondary address information was considered invalid. We provide full definitions of these status codes in our data dictionary.
Unfortunately, because National Change of Address information is consumer sourced, even regular NCOA processing will not prevent all returned mail. In addition, there are a number of non-move related reasons an address may not be deliverable. If you receive a yellow NIXIE label with USPS returned mail codes, you can determine why the piece of mail was returned.
Some of the most common nixie mail codes:
- Attempted Not Known (ANK): Delivery attempted, addressee not known at place of address
- Deceased (DEC): Used only when addressee is deceased and mail is not properly deliverable to another person
- In Dispute (DIS): Cannot be determined which disputing party has better right to mail
- Insufficient Address (IA): Necessary address details omitted and correct address not known
- Illegible (ILL): Address not readable
- No Mail Receptacle (NMR): Addressee failed to provide a receptacle for receipt of mail
- No Such Number (NSN): Addressed to nonexistent number and correct number not known
- No Such Street (NSS): Addressed to nonexistent street and correct street not known
- Refused (REF): Addressee refused to accept mail or pay postage charges
- Unclaimed (UNC): Addressee abandoned or failed to call for mail
- Not Deliverable As Addressed - Unable to Forward (UTF): Mail undeliverable at address given; no change-of-address order on file; forwarding order expired
- Vacant (VAC): House, apartment, office, or building not occupied
A full list of NIXIE return to sender reasons and their definitions can be found here.