When we lend to people with ITIN numbers and report the loan to the credit bureaus, can we report the ITIN number? I have a memory that the answer is no but I can't remember where I've seen that. Is it a FCRA violation?

Metro 2 Guide under reporting the SSN:

Notes:

If the Social Security Number is not reported, the Date of Birth is required to be reported.

Do not report Individual Tax Identification Numbers (ITINs) in this field. ITINs do not prove identity outside the tax system and should not be offered or accepted as identification for non-tax purposes, per the Social Security Administration.