Here's an excerpt from Cheryl Riedlinger's
(The Tax Reporting Group) handout at the June ABA Regulatory Compliance Conference:
Under the Tax Reconciliation Act of 2001 the backup withholding rate decreases from 31% to 30.5% this year, and then an additional small amount each year to reach 28% by 2006. This change is effective within 60 days after enactment, i.e. August 7, 2001. It will require reprogramming and a change to IRS substitute Forms W-9, W-8, etc. which refer to a specific 31 percent backup withholding rate. Due to the phase-in of the new rates over five years, banks should revise forms to include a reference to "backup withholding under Section 3406 of the Internal Revenue Code" and not indicate a specific rate to avoid annual and costly revision of forms.