Undeliverable-as-Addressed (UAA) Statistics by Mailing Industry Quarterly Report (Q1 FY26)

ACS Nixie stats by industry for FY26 Q1.

December 2025 Nixie Volume

This spreadsheet contains the UAA statistics for December 2025.

ZIP Codes by Area and District codes

The Excel spreadsheet lists ZIP Codes with the associated Area and District Codes.  

Z4 Info File

A downloadable ZIP file containing information related to the Z4 Info File

Early Warning System (EWS002C0.ZIP)

This file is the EWS production file and is updated weekly. This file contains the Early Warning System data file for the CASS™ and MASS™ certification process.

Labeling List Changes Effective February 1, 2026

Effective February 1, 2026, the Postal Service™ will revise Labeling List(s) L002, L005, L012, L016, L051, L201, and L606 to reflect changes in mail processing operations. Mailers are expected to label according to these revised lists for mailings inducted on or after the February 1, 2026, effective date through March 31, 2026, expiration date. The changes will be published in the Postal Bulletin, Issue #22694.

***Updated - New Areas*** - Area District 5-digit ZIP Codes (AREADIST_ZIP5.TXT)

City/State ZIP Code Weekly Compare

3 Digit ZIP/AISU Office List (AISUREPT.TXT)

AIS Congressional District File (CONG_DIST.TXT)