PMB Addressing Rules for CMRA Customers

Under DMM 508.1.8.3, mail addressed to a CMRA customer must identify the private mailbox with "PMB" followed by the box number, or the "#" sign followed by the box number, in one of two positions:

• On its own line, directly above the street address line.
• Appended to the end of the street address line.

That is the whole rule. Everything else, Suite, Ste, Apt, Unit, Dept, is a designator for a physically distinct space, and USPS prohibits using them to dress up a private mailbox.

The last non-compliant example is the subtle one: if your store itself sits in Suite 100, the customer's designator is still PMB, and mixing suite and PMB designators for the box invites exactly the scrutiny the rule exists to prevent. Keep your store's own suite on your business address, not on customer boxes.

The designator exists so that mail to a private mailbox is identifiable as such. A store whose customers use Suite addresses looks, to USPS, like a store helping customers misrepresent a mailbox as a physical office. That reads as a compliance posture problem, not a formatting one, and it is visible on every envelope that moves through the system.

Enforcement follows the same track as other CMRA deficiencies: suspension for non-compliance, with termination of the authorization possible if it is not cured within 30 days.

• Issue the address, do not negotiate it. Give every new customer their exact compliant address at Form 1583 time, in writing.
• Use one format across the whole store. Uniformity is itself part of the expectation, and mixed formats make audits longer.
• Offer the # form to customers worried about appearances. It is compliant and reads neutrally.
• Re-check the roster when you inherit customers from an acquisition or a migration from another operator; legacy Suite addresses are a common inherited defect.