ITIN:
- A tax processing number, issued by the IRS for certain resident and non-resident aliens, their spouses and dependents.
- All valid ITIN's are a nine-digit number in the same format as the SSN (9XX-8X-XXXX), begins with a "9" and the 4th and 5th digits range from 50 to 65, 70 to 88, 90 to 92, and 94 to 99.
- Individual Taxpayer Identification Numbers (ITIN's) that haven't been included on a U.S. federal tax return at least once in the last three consecutive tax years will expire.
For more information: http://www.irs.gov/Individuals/General-ITIN-Information
https://www.irs.gov/pub/irs-pdf/p4757.pdf