Secondary address information is information more specific than the building number, such as apartments and suites.
A catalog addressed to 400 Main Street is unlikely to arrive at the intended recipient's mailbox if that person lives at 400 Main Street, Apartment 404B.
Incomplete address information can lead to:
Front-end address verification software protects databases from incomplete address information. A solution will prompt for secondary address information in any address that the USPS® recognizes as having secondary address information.
Back-end software cleans up existing databases and flags addresses that are missing secondary address information, enabling companies to seek out more accurate information before continuing to mail to an address.