I donu2019t understand this question. The word u201cactivityu201d does not appear in the W-9 instructions, and appears in Form W-9 itself only in the context of advice to taxpayers regarding protecting their identity. The phrase u201cUnited States Activityu201d does not, to me, seem to have any relevance to the circumstances in which Form W-9 is required to be requested.If you have been asked to prForm W-9 by another party, itu2019s because that party has concluded that it needs to have your taxpayer identification number because it has, or expects to, engage in a reportable transaction with you for which it needs your taxpayer identification. They are required to ask you to pryour taxpayer identification information on Form W-9 (if you are a US resident for tax purposes) or one of the variations on Form W-8 (if you are not a US resident for tax purposes). The IRS will never ask you to prthem with Form W-9 directly.You are not necessarily required to prthem with Form W-9 when asked, but if you donu2019t they may be required to withhold additional taxes from any payments they would otherwise make to you, and may elect to withdraw from the transaction which they have concluded is reportable to the IRS. If you believe that the transaction that you are being asked to prForm W-9 in connection with is not a reportable transaction, you need to discuss that with whoever is asking you to prthem with Form W-9. Businesses often ask for Form W-9 even from entities with whom they engage in wholly non-reportable transactions. You can refuse to prthe form (youu2019re never required to prForm W-9 or one of the Form W-8 variants) but your refusal may have adverse effects on your relationship with that entity.If you are trying to determine if you need to request a party with whom you are doing business to pryou with Form W-9 (or a variant of Form W-8 as is appropriate), thatu2019s a much more complex question, and one which you should address to your tax compliance advisor for advice specific to your situation.