My wife recieved a letter from Citibank, that looked official. It had her SS # and her birthday on it, and asked her to fill out a W9 Identification form, and mail it to them in the envelope provided. Everything looked legitamate, even the address on the envelope. We called Citibank to question it, and it is a scam. We were told that it is a common one. They said they never send out letters asking for information. Do not send anyone anything, without verifying it first.