When does a company require my social security 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 will have a broker clear them on their behalf.
Because many foreign merchants are aware that CBP requires an identification number for the ultimate 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.
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 importer's identification number is either the EIN/tax identification number assigned by the IRS or the importer's social security number
Please visit US Customs and Border Protection website for more information.