FATCA reporting — Form 8966 & local IGA portals: data mapping, validations & reviewer-ready evidence
Whether you report via a Model 1 portal or file Form 8966 directly with the IRS under Model 2, clean reporting hinges on stable data mapping, pre-submission validations, and a tidy evidence pack. This guide shows what to map, how to validate, and what to keep for audits and reviews.
Scope: Data flows for FATCA reporting, including Form 8966 and local IGA portals, validations, receipts, corrections and governance.
Pair this with your corrections playbook and data dictionary.
1) Data model — the minimums to map
Keep a living data dictionary with source-to-target mappings and lock versions per filing year.
| Concept | Examples of fields | Source systems |
|---|---|---|
| Entity / account identity | Legal name, address/country, TIN, GIIN if applicable, account number | KYC / CRM, core banking |
| FATCA status | Chapter 4 classification, IGA model, sponsor/sponsored relationships | KYC / tax master, GIIN tracker |
| Reportable values | Account balance/value, gross payments, currency, FX rate/method, reporting period | Ledger / subledgers, data warehouse |
| Contacts & consent | Email/address for notices, consent record, especially for Model 2 | KYC, e-consent platform |
Document transformations, such as currency conversions, country ISO codes and TIN normalization, with explicit rules.
2) Validations before you hit submit
- Schema / version gate: export uses the correct schema for the year and portal; reject if mismatched.
- Identity checks: name not blank; country is ISO; TIN formats validated; GIIN format validated where provided.
- Status logic: if status requires a GIIN, ensure the GIIN is present and found on the monthly FFI list.
- Thresholds: apply local IGA or Form 8966 thresholds consistently.
- Currency rules: use a consistent FX source/date and document rounding.
- Duplicates: use unique record keys and stable account identifiers per year.
Keep a one-page validation summary with counts, failed rules and maker-checker sign-off.
3) Submissions, receipts and error handling
- Package files; record hash or checksum if available; log version numbers.
- Submit via the relevant local portal or IDES; capture submission ID, receipt and any error report.
- Resolve rejects through a corrections and re-filings log.
- Archive receipt, error report, corrected files and communications.
For nil filings, still keep screenshots or receipts where the portal provides them.
4) Evidence pack — what reviewers expect
- Data dictionary with source-to-target mappings, transformations, versions and owners.
- Validation summary with rules, results, thresholds applied and maker-checker sign-offs.
- Submission receipts and error reports, including IDs, timestamps and hashes where available.
- Corrections dossier with before/after diffs, approvals and re-submission receipts.
- Policy note covering governance, responsibilities, retention, privacy and consent for Model 2.
5) Quick controls that reduce re-work
- Freeze the reporting dataset on a specific date; no silent refreshes.
- Version-lock mappings per year and log any updates.
- Automated GIIN match for all GIIN-dependent statuses in scope.
- Schema unit tests embedded in the build/export pipeline.
- Maker-checker approvals for submissions and all corrections.
Reporting pack starter templates
Data dictionary, validation checklist and submission receipts log.
Data dictionary, validation checklist and submission receipts log.
Want your reporting flow QA’d?
We map sources, lock validations, dry-run submissions, and package a clean dossier with receipts.
We map sources, lock validations, dry-run submissions, and package a clean dossier with receipts.