The signature card we will be using on the online account opening, IT wants to mask the SSN on the back up withholding section. I do not think we can since the customer is certifying that the SSN is correct and not subject to backup withholding. Also, I remember that the government can ask to see the certification that the customer signed and certified. All we would be able to show them would be XXX-XX-1234 which would not be the number they certified.

Does anyone have any support for me that we can not mask that section?

Is the full TIN shown elsewhere on the signature card? Ours prints below the customer signature and in the W9 box. Since a regular Form W9 references 'the number shown on this form' without repeating the number at all, masking it when it appears a second time wouldn't seem to be an issue. But if it's already on the same form, what's the point of masking it at all?