What Is a Customs Assigned Importer Number (CAIN)?

Customs Assigned Importer Number (CAIN) An importer number assigned by U.S. Customs and Border Protection to an importer that does not use an IRS EIN or SSN for customs purposes.

The Customs Assigned Importer Number (CAIN) is a unique identifier issued by U.S. Customs and Border Protection (CBP) when an importer lacks a domestic tax identifier such as an IRS Employer Identification Number (EIN) or Social Security Number (SSN). CBP uses this number in import documentation, manifests, and entry processing to establish an importer of record for shipments arriving into U.S. commerce.

Why CAIN Exists

Customs requires an importer identifier on filings to link shipments to the responsible party for duties, taxes, and compliance. Foreign-based importers, U.S. individuals without an EIN, and entities in transition (for example, those awaiting an EIN) may not have a standard IRS number. The CAIN provides CBP a reliable, internal identifier so entries can be processed and enforcement and statistical functions can proceed.

How CAIN Is Used By CBP

CAIN is recorded on entry summaries, manifests, and Automated Commercial Environment (ACE) transactions. It establishes the importer of record for purposes including duty assessment, recordkeeping, and enforcement actions. In some cases, carriers or brokers will reference a CAIN on bills of lading and arrival notices so port offices and CBP systems can match cargo to the importer.

Who Typically Receives A CAIN

• Foreign Importers: Non-U.S. based companies that import directly into the U.S. and do not have an EIN.
• U.S. Individuals Without SSN/EIN: Small or occasional importers and certain private individuals.
• Entities Awaiting Tax Numbers: Businesses in formation or changing tax status pending an EIN.

How CAIN Is Issued

CAIN issuance is handled by CBP. Filing parties typically request assignment through their port of entry or the CBP office responsible for the transaction. For ACE filings, brokers and importers can coordinate with CBP to ensure a CAIN is created and accepted by automated systems. The process varies by port and the details are recorded in CBP systems so the number can be reused on subsequent entries.

Practical Example

A German manufacturer that imports components into the United States for assembly lacks a U.S. EIN. Their customs broker applies for a CAIN and uses it on the ACE entry transaction. CBP uses the CAIN to identify the importer of record, assess duties, and store the importer’s records for audit — while the importer remains a foreign entity without a U.S. tax number.

Common Operational Considerations

• Data Consistency: Ensure the importer name, address, and CAIN match across ocean/air waybills and customs entries to avoid delays.
• Transition To EIN: If an importer later obtains an EIN, update filings and notify CBP to migrate records and avoid duplicate identities.
• Broker Coordination: Freight forwarders and customs brokers usually handle CAIN requests — confirm they provide the assigned number in writing.

In short, the Customs Assigned Importer Number (CAIN) is a CBP-issued identifier that allows import processing and compliance when an importer lacks an IRS EIN or SSN. Proper use and recordkeeping of the CAIN prevents delays, supports duty assessment, and links entry records to the correct importing party.