U.S. Shipping

SSN (Social Security #) or EIN (Employee Identification #) required for Shipments imported to the USA and valued at over $1,000 – $2,500.00

This information is required by USA customs for high value imports.

The following is link to a page directly from the USA customs:
Importers – Social security number / Tax Identification Number / IRS Number / Importer Number requested by overseas supplier

Further, other well known, large companies also stipulate this required policy.  As an example, here is a link to the Federal Express website page regarding this policy.

The threshold stipulates values of $2500.00 or above, but to avoid delay freight forwarders require this number if the purchase is higher than $1000.00.  Otherwise the entire shipment might be delayed and more expenses might be incurred in storing the goods at the border.