An FTIN is a taxpayer identification number issued by a country other than the United States. Depending on the country, this number might be a government-issued identification card or social insurance card. Non-US investors wishing to invest into an SPV need to provide information for a KYC/AML background check and tax documents, like a W8-BEN or W8-BEN-E. Many times a FTIN is necessary to complete these checks and forms.