12 CFR 1070.63: Use and collection of Social Security numbers.

The CFPB will ensure that employees authorized to collect information are aware:

(a) That individuals may not be denied any right, benefit, or privilege as a result of refusing to provide their Social Security numbers, unless the collection is authorized either by a statute or by a regulation issued prior to 1975; and

(b) That individuals requested to provide their Social Security numbers must be informed of:

(1) Whether providing Social Security numbers is mandatory or voluntary;

(2) Any statutory or regulatory authority that authorizes the collection of Social Security numbers; and

(3) The uses that will be made of the numbers.