Masking
Mask the Recipient's TIN
Specify whether to print the recipient’s taxpayer identification number (TIN) as masked or unmasked on payee statements. When you enter 1 in this field, the system prints only the last four digits of the recipient's TIN (for example, XXX-XX-6789) on Copy B of the 1099 form. If you leave this field blank, the nine-digit TIN is printed on the payee statement.
Values are:
Blank: Print the nine-digit TIN without masking.
1: Print the last four digits and mask the the first five digits of the TIN (for example, XXX-XX-6789).
Important: You must ensure that the TIN on Copy A of the 1099 form is unmasked and contains the nine-digit TIN before you submit it to the IRS.