FATCA XML Schemas Best Practices for Form 8966 DocRefId


The <DocRefId> data element is a unique identifier and reference for each account, pooled, or nil report. It pools reports across all reporting financial institutions and periods. In addition, each reporting FI, sponsor and intermediary should have a unique <DocRefId> associated with each record.  For more information, review IDES Technical FAQs.

The following format is required for standardized DocRefIds effective January 1, 2016:



Size Minimum of 21 characters
Maximum of 200 characters
Datatype xsd: string
Pattern <ReportingGIIN>.<UniqueValue>
  • <ReportingGIIN> is the GIIN for the reporting FI associated with the reporting group
  • Period character (.)
  • <UniqueValue> is an identifying value for the referenced record that is unique within the reporting FI for all time.
  • Use of a globally unique identifier (GUID) is recommended.
  • The DocRefID must not include any non-alphanumeric characters, excluding periods and dashes. Prohibited non-alphanumeric characters include but are not limited to_, @, +, &, ! and *.
  • S519K4.99999.SL.392.12291cc2-37cb-42a9-ad74-06bb5746b60b
  • 127BM7.00001.ME.124.406abc8a1830490e847890ba3b13a646