Just got a letter from Mortgage Company The are being required to verify the Social Security number of the mortgage holder.  I was ok with that but something caught my eye that I have never seen. This is the exact sentence "The IRS requires, subject to penalty, that we obtain your TIN (Taxpayers Identification Number/Social Security Number) in order for us to report annually the amount of interest collected from you.  When did they change social security to tax payer identification?  Just curious.