A GIIN is a 19-character alphanumeric identifier formatted as XXXXXX.XXXXX.XX.XXX. Each segment carries a specific meaning. This guide breaks down every character and explains what each component tells you about the institution.
The 19-character structure
| Position | Length | Component | Rules |
|---|---|---|---|
| 1–6 | 6 | FATCA ID | Uppercase letters + numbers. Never contains the letter "O". |
| 7 | 1 | Separator 1 | Always a period (.) |
| 8–12 | 5 | Type | Uppercase letters + numbers. Determined by entity type. |
| 13 | 1 | Separator 2 | Always a period (.) |
| 14–15 | 2 | Category Code | Uppercase letters only |
| 16 | 1 | Separator 3 | Always a period (.) |
| 17–19 | 3 | Country Code | ISO 3166-1 numeric. 999 = "Other". |
FATCA ID (positions 1–6)
The first six characters identify the FATCA registration group. How this is populated depends on the entity type:
- Lead FI, Single FI, Sponsoring Entity: Same as the entity's FATCA ID.
- Member FI: First 6 characters of the member's FATCA ID.
- FI branch: First 6 characters of the associated FI's FATCA ID.
- Sponsored entity: The sponsoring entity's FATCA ID.
Type code (positions 8–12)
- Lead FI:
00000 - Single FI:
99999 - Sponsoring entity:
00000 - Member FI: Last 5 characters of the member's FATCA ID.
- FI branch: Same as the associated FI.
- Sponsored entity: Last 5 characters of the sponsored entity's ID.
Category code (positions 14–15)
| Code | Meaning |
|---|---|
LE | Lead FI |
SL | Single FI |
ME | Member FI |
BR | FI Branch |
SP | Sponsoring Entity |
SF | Sponsored Fund |
SD | Sponsored Direct Reporting NFFE |
SS | Sponsored Subsidiary |
SB | Sponsored Subsidiary Branch |
Country code (positions 17–19)
The final three digits are the ISO 3166-1 numeric country code of the jurisdiction that issued the registration. Common examples:
356— India276— Germany442— Luxembourg826— United Kingdom124— Canada840— United States999— Other
Worked examples
| GIIN | Breakdown |
|---|---|
ABCDEF.12345.SL.356 | FATCA ID ABCDEF · Type 12345 · Category Single FI · Country India |
ABCDE1.00000.LE.276 | FATCA ID ABCDE1 · Type 00000 · Category Lead FI · Country Germany |
ABCDE2.23456.ME.826 | FATCA ID ABCDE2 · Type 23456 · Category Member FI · Country UK |
Common format mistakes
- Using lowercase letters — only uppercase are valid.
- Using the letter "O" — never appears in a GIIN.
- Wrong number of characters per segment.
- Missing or incorrect periods between segments.
- Using a 2-letter country code instead of the 3-digit numeric code.
- Copying from PDFs or emails that introduce hidden whitespace.
Validate a GIIN format
You can check the format of a GIIN with a simple regex:
^[A-Z0-9]{6}\.[A-Z0-9]{5}\.[A-Z]{2}\.\d{3}$Format validation only confirms the structure — it does not confirm the GIIN exists on the IRS FFI List. For that, use our GIIN Lookup tool.
Related resources
- GIIN Lookup — search the live FFI List
- How to Find Your GIIN — IRS portal guide
Frequently asked questions
How many characters is a GIIN?
19 characters total, including three period separators — 6+1+5+1+2+1+3.
Can a GIIN contain the letter O?
No. The letter "O" is excluded to avoid confusion with the digit zero.
What does the country code at the end mean?
It's the ISO 3166-1 numeric code of the jurisdiction that issued the FATCA registration. 999 is used for "Other".
Is my GIIN the same for FATCA and CRS?
CRS does not use the GIIN. Under CRS, financial institutions are identified by their local tax identification number or the reporting FI's own identifier. The GIIN is a FATCA-specific identifier.
Does the GIIN format change between Model 1 and Model 2?
No. The format is identical. The difference between Model 1 and Model 2 is where the information is reported (local authority vs IRS directly), not how the GIIN is structured.