Why is an overseas supplier requesting my social security number - SSN, EIN (tax identification number), importer or IRS number?
When goods enter the United States from overseas, it is considered an importation and must be cleared by Customs and Border Protection (CBP).
When an individual or company purchases goods from an overseas supplier, CBP considers them the ultimate importer. The ultimate importer can clear the goods or have a broker clear them on their behalf.
If the supplier hires a carrier that provides door to door service, the carrier service usually has brokers in their supply chain to clear the goods on behalf of the ultimate importer. If a formal entry is required, CBP regulations require the broker to put the ultimate importer's identification number on the Entry Summary CBP Form 7501. The ultimate imorter's identification number is either the EIN/tax identification number assigned by the IRS or the importer's social security number. A formal entry is usually required for commercial importations valued at $2,000 or more.
Some commodities subject to quota or other agency requirements when imported for commercial (non personal) purposes require a formal entry no matter what the value (i.e., textiles).
If the goods are cleared informally, the Entry Summary CBP Form 7501, bond and identification number are not required. Goods are usually cleared informally when they are for personal use, under $2000 in value, and are not in commercial quantities. However, because there are no guarantees that an entry will be cleared informally, brokers find it helpful to have the ultimate importer's identification number just in case.
Because many foreign merchants are aware that CBP requires an identification number for the ulitimate importer for formal entries, they will often request the purchaser's social security number to include on export documents that the broker will subsequently rely on to prepare the CBP entry.
It should be noted that paperwork for goods sent by courier service does ask for an importer number, whether the import qualifies for an informal entry or not. Courier services file CBP entries electronically, and the software system they use requires an identification number to be provided for the recipient of the goods. If an identification number is not provided, the courier service is required to file a paper entry, which is extremely time-consuming and in the world of "Overnight Delivery" not practical. The end result is that most courier services will not accept packages for international delivery to U.S. residents if a recipient's identification number is not provided by the shipper. Goods sent thru the international postal service that are under $2000 in value generally do not require an importer number to be cleared through CBP.