Microsoft Federal Tax ID, W-9 and DUNS
Microsoft's federal tax ID is 91-1144442. Should you require a W-9 form from Microsoft, email the Microsoft Ignite support team at ignite@microsoft.regsvc.com with the subject line, "ATTN: FINANCE, W-9 Request."
The Microsoft DUNS number is 08-146-6849.
If you are not attending Microsoft Ignite but are seeking a W-9 for purchases made at a Microsoft Store, contact taxexmpt@microsoft.com for assistance.