You shall pay the Internal Revenue Service withholding tax equal to the amount that you would have paid over the course of a calendar year if any withholding tax had been withheld from the amount of backup withholding payments that you have been made (as of the end of the calendar year in which the collection is made) and any amount withheld pursuant to section 2042 of title 28, United States Code. Additional Resources: The IRS provides a wealth of resources for taxpayers, including some excellent publications that include guidance on how the Form W-9 process works. The Form W-9 FAQ helps answer frequently asked questions.