You don't normally send a W-9 to someone to whom you pay rent. According to the IRS web site, you need a business or individual's tax ID number under the following circumstances: 'A person who is required to file an information return with the IRS must obtain your correct taxpayer identification number (TIN) 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 to an IRA.' If you keep copies of your rent receipts or cancelled checks, that should be all you need. You will report the rent paid as a business deduction on your taxes. Unless there are special circumstances, you shouldn't need to file an information return with the IRS. An information return is not the same as a tax return. Information returns include documents like a 1099MISC that you give to someone to whom you paid wages (income) of more than $600 for work done for your company, or the form a bank sends to report mortgage interest paid or student loan interest paid. Do you have some reason to believe that the company is not paying taxes on their income? If so, that shouldn't affect you as long as you have records of payments you made.