CAIN vs EIN: When Importers Need a Customs Assigned Importer Number

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.

Importers and brokers often ask whether to use an IRS Employer Identification Number (EIN) or a Customs Assigned Importer Number (CAIN) on U.S. customs filings. The answer depends on whether the importer has access to a domestic tax identifier and how the importer is structured. This article clarifies when a CAIN is appropriate and the implications compared with using an EIN.

Primary Difference

An EIN is issued by the Internal Revenue Service and serves broadly as a tax identifier for businesses operating or filing taxes in the United States. A CAIN is a CBP-issued identifier used specifically for customs transactions when an EIN or SSN is unavailable. EINs are preferred for long-term U.S. operations because they integrate across federal systems; CAINs are a customs-specific workaround.

When CAIN Is The Correct Choice

• Foreign Parent Companies Importing Directly: If a foreign corporation imports into the U.S. but has not registered for U.S. taxes, CBP can assign a CAIN for entries.
• Non-Resident Individuals: Individuals without SSNs who import occasionally may rely on CAINs for customs filings.
• Short-Term or Trial Imports: Businesses testing U.S. markets before forming a U.S. legal entity may use a CAIN temporarily.

When You Should Obtain An EIN Instead

• Establishing Long-Term U.S. Operations: If a company expects recurring imports, hiring staff, selling in the U.S., or filing U.S. taxes, obtain an EIN and migrate customs filings to it.
• Customs Broker Requirements: Some brokers or carriers prefer or require an EIN for automated processing and financial responsibility.
• Regulatory Registrations: For FDA, USDA, or other agency registrations tied to business operations, an EIN is often required.

Operational Impacts Of Using CAIN Versus EIN

Using a CAIN can simplify immediate clearance when no EIN exists, but it creates additional reconciliation steps. When an EIN is later obtained, importers should update CBP and their brokers so duty assessments, record audits, and trade statistics correctly reflect the EIN. Failure to align identifiers can lead to duplicate importer records, difficulties in audits, and disruption in automated matching of entries to payment or bond records.

Practical Migration Steps

• Obtain an EIN Early: Apply via the IRS (online or by mail) when planning sustained U.S. imports.
• Notify CBP and Broker: Once an EIN is assigned, notify your customs broker and the servicing port to update the importer profile and migrate active CAIN entries.
• Consolidate Records: Keep a record mapping CAIN-to-EIN assignments so auditors and compliance teams can reconcile historical filings.

Example Scenario

A UK company makes a one-off shipment of parts to a U.S. distributor and does not have a U.S. EIN. The customs broker requests a CAIN so the cargo clears. Six months later the company forms a U.S. subsidiary and secures an EIN. The broker updates future entries to the EIN and provides documentation to CBP to link the old CAIN history to the new EIN to prevent confusion during audits.

In short, the Customs Assigned Importer Number (CAIN) is a practical CBP identifier for importers without an EIN or SSN, but it is not a substitute for the broader legal and tax functions of an EIN. Use CAIN for short-term or foreign-based importing and obtain an EIN as soon as sustained U.S. activity begins to simplify compliance and reduce administrative overhead.