a paper Form W-9, that a hard copy can be supplied to the IRS on demand, that "the information received is the information sent and […] all occasions of user access that result in the submission [are documented]", that the person accessing the system and providing the information is the individual identified on the form, and that an electronic signature is used. Deadline Some certified public accountants consider it best practice to ensure the completion of Form W-9 by payees before issuing any payments. There may also be a $50 penalty for each instance in which Form W-9 is not filled out. See also Foreign Account Tax Compliance Act External links Fillable PDF version of IRS W-9 Form References W-9