How can the original ATO be identified?

• A. ATO name
• B. Date of issue
• C. Authorization code
• D. Unique ID in Field 3 of the MSGID

Answer: (D)

The key idea is that a Unique ID in the MSGID’s Field 3 is the definitive way to identify the original ATO. This identifier is designed to be unique to each ATO and stays with that document as it’s transmitted, copied, or amended. In contrast, an ATO name, date of issue, or an authorization code can be shared across multiple ATOs or may appear on revised versions, so they don’t reliably distinguish the original. By using the Unique ID in Field 3 of the MSGID, you have a single, unambiguous reference that confirms you’re looking at the exact original ATO.