You did not state who is asking for a W-9 form, or for what reason they are requesting it. A person (or business) who is required to file an information return with the IRS must obtain your correct taxpayer identification number (TIN) or SSN to report, for example, income paid to you, real estate transactions, mortgage interest you paid, acquisition or abandonment of secured property, cancellation of debt, or contributions you made to an IRA.
If you are getting interest or other income reported to you, like for instance interest from a savings account, they will need to report that taxable income they paid to you, to the IRS. If they have collected taxable interest from you (mortgage interest for example), they need to report that as income they received.
If you are getting interest or other income reported to you, like for instance interest from a savings account, they will need to report that taxable income they paid to you, to the IRS. If they have collected taxable interest from you (mortgage interest for example), they need to report that as income they received.