Reference IDs on Form 5472: Format, Continuity, and Missing U.S. IDs
· 6 min read
The practical answer
A reference ID is most useful when it identifies the same person consistently across filing periods. The preparation task includes checking earlier records and the permitted format, not just inventing a convenient label while completing the current form. A reference ID may consist of letters only, numbers only, or a combination of letters and numbers, with no spaces or special characters and no more than 50 characters. Keep it consistent for the same person across years, and do not reassign a discontinued ID to another person.[1, p.4]
Scope and the records behind the answer
The discussion follows the entity, form and transaction conditions identified below. The same label on a different form can have a different purpose. Keep the relevant entity and reporting period visible while you compare the requirements, and treat each stated exception as part of the rule rather than an optional footnote.
Official sources checked: 2026-11-09. Annual tax-year forms and continuously revised forms are identified separately in the references.
A side-by-side preparation table
| Item or question | Official rule or instruction | Conditions and limits | Source |
|---|---|---|---|
| Reference id format | A reference ID may consist of letters only, numbers only, or a combination of letters and numbers, with no spaces or special characters and no more than 50 characters. Keep it consistent for the same person across years, and do not reassign a discontinued ID to another person. | Apply this entry within the entity, form and period described here; read the cited passage for the surrounding context. | [1, p.4] |
| Reference id when missing us id | When the applicable foreign shareholder has no U.S. identifying number entered in Part II, use the reference ID required by the instructions. The reporting entity or its representative creates this ID; it is not a separate IRS application. | Apply this entry within the entity, form and period described here; read the cited passage for the surrounding context. | [1, p.4] |
| Field/section 8b(2): Reference ID number (see instructions) | For the applicable foreign related party without a U.S. identifying number, use a reference ID in the prescribed format and keep it consistent across years. | Apply this entry within the entity, form and period described here; read the cited passage for the surrounding context. | [2, p.2] [1, p.5] |
| Field/section 8b(1): U.S. identifying number, if any | Enter the related party's U.S. identifying number, if any: SSN or ITIN for an individual, or EIN for another entity. | Apply this entry within the entity, form and period described here; read the cited passage for the surrounding context. | [2, p.2] [1, p.5] |
Work through the official requirements
Reference id format
A reference ID may consist of letters only, numbers only, or a combination of letters and numbers, with no spaces or special characters and no more than 50 characters. Keep it consistent for the same person across years, and do not reassign a discontinued ID to another person.[1, p.4]
Reference id when missing us id
When the applicable foreign shareholder has no U.S. identifying number entered in Part II, use the reference ID required by the instructions. The reporting entity or its representative creates this ID; it is not a separate IRS application.[1, p.4]
Field/section 8b(2): Reference ID number (see instructions)
For the applicable foreign related party without a U.S. identifying number, use a reference ID in the prescribed format and keep it consistent across years.[2, p.2] [1, p.5]
Field/section 8b(1): U.S. identifying number, if any
Enter the related party's U.S. identifying number, if any: SSN or ITIN for an individual, or EIN for another entity.[2, p.2] [1, p.5]
An illustrative preparation scenario
In this hypothetical preparation example, a preparer sees one reference ID in last year's file and a different proposed label in the new intake sheet. The owner has not changed. The review reconciles the history, checks the characters and length, and records which identifier belongs to that person before completing the new packet. The preparer checks three points: Does a reference ID already exist for this person? Does its format meet the instructions? Has any discontinued identifier been reassigned improperly? The file remains a working comparison until the relevant facts and applicable instructions have been checked together. No agency outcome is assumed.[1, p.4]
For a separate hypothetical continuity check, two people in a reporting file share similar names, and a new worksheet gives both the same shortened reference label. Earlier forms show a distinct identifier for each person. The preparer reconciles those histories before testing the permitted characters and length. A register then links each identifier to its person and previous use, so an abbreviation introduced for convenience does not silently merge identities or recycle an identifier that belonged to someone else. Continue that comparison by adding the person's legal name, the earlier reference ID, the relevant form section, and the years of use to the working register. Where names have different spellings, reconcile the underlying identity before treating them as different people. Record whether the applicable field contains a U.S. identifying number and why the reference-ID instruction is relevant. These links let a later preparer trace continuity back to the earlier filing instead of choosing a fresh label from the latest spreadsheet.[1, p.4]
This is a planning illustration, not a statement that a particular filing has been accepted or that an entity qualifies for a tax result. Use the source-backed distinctions above to decide what information still needs to be established before a form is completed.
A review sequence you can actually use
- Does a reference ID already exist for this person?
- Does its format meet the instructions?
- Has any discontinued identifier been reassigned improperly?
Write down the answer and the record that supports it, rather than marking a question complete because a field contains text. When two records disagree, identify whether the difference concerns the entity, an individual, the reporting period or the type of change. That makes the remaining question specific enough to resolve against the relevant instruction.
Keep the scope of a preparation service separate from the government requirement. A service intake question may gather information for a workflow; it does not create an exception, extend a deadline or determine whether a transaction is reportable. The cited government material remains the basis for those conclusions.
Questions to settle before moving forward
How should I check field/section 8b(2): reference id number (see instructions)?
For the applicable foreign related party without a U.S. identifying number, use a reference ID in the prescribed format and keep it consistent across years. [2, p.2] [1, p.5]
How should I check field/section 8b(1): u.s. identifying number, if any?
Enter the related party's U.S. identifying number, if any: SSN or ITIN for an individual, or EIN for another entity. [2, p.2] [1, p.5]
Official sources and versions
- Instructions for Form 5472 (Rev. December 2024) — Rev. December 2024
- Form 5472 (Rev. December 2023) — Rev. December 2023
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