When did Fedwire implement the CPMI harmonised ISO 20022 data model requirements, and what postal address format does Fedwire require for the hybrid/end-state approach?
The model over-specified the mandatory field tier. The implementing body's published FAQ places Building Number, Post Code, and Country Sub-Division in the optional tier; the model elevated them into a more rigid structured-element category that does not match the published specification. This is a schema over-specification failure — the mandatory/optional boundary was shifted toward greater structure than the regulator's own implementation guide defines, which would cause a practitioner applying the model's output to implement a more restrictive address format than required.
This failure implicates retrieval coverage of implementing-body FAQ layers. When the FRB Services FAQ defining the hybrid/end-state postal address format is not retrieved, the model reconstructs the mandatory/optional field boundary from training, and reconstruction tends toward over-specification — adding Building Number, Post Code, and Country Sub-Division to the mandatory tier where the FAQ places them as optional. The RAG or retrieval glue is not surfacing the implementing body's own technical specification when it conflicts with a more structured internal representation.
The Fedwire hybrid postal address format specifies optional free-format lines of 70 characters each for the unstructured component — not optional structured fields such as Street Name, Building Number, and Post Code. AI tools we tested inverted this, substituting structured optional elements drawn from general CBPR+ address schema knowledge. That substitution would be invisible in a first-read review of an advice memo or compliance annex.
A lawyer who includes the AI's description in implementation guidance delivered to a Fedwire participant, or in a sign-off on a compliance specification, has delivered a technically wrong answer about a named system's format requirement — with PI exposure that is difficult to disclaim once the description appears in a client deliverable.
Each finding has a stable Citation ID (RLB-F-… for aggregated case-study findings, RLB-H-… for raw per-model hallucinations) — like a DOI, the ID always resolves to the canonical finding even if URLs change.
RegLeg Specialist Panel, Finding#4 — Fedwire hybrid address optional component inverted from free-format to structured fields [RLB-F-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010], RegLegBrief AI Hallucination Research (June 04, 2026), https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iso-20022-harmonisation-updated-2026/practitioners/lawyers/finding/INT-BIS-CPMI-INT-001-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-v1-010/.
RegLeg Specialist Panel (2026). "Finding#4 — Fedwire hybrid address optional component inverted from free-format to structured fields — Practitioners — Lawyers." Citation ID: RLB-F-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010. RegLegBrief AI Hallucination Research, published 2026-06-04. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iso-20022-harmonisation-updated-2026/practitioners/lawyers/finding/INT-BIS-CPMI-INT-001-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-v1-010/
RegLeg Specialist Panel. (2026). Finding#4 — Fedwire hybrid address optional component inverted from free-format to structured fields [Hallucination finding RLB-F-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iso-20022-harmonisation-updated-2026/practitioners/lawyers/finding/INT-BIS-CPMI-INT-001-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-v1-010/
@misc{reglegbrief_RLB_F_INT_BIS_CPMI_ISO_20022_HARMONISATION_UPDATED_2026_Q010,
author = {RegLeg Specialist Panel},
title = {Finding#4 — Fedwire hybrid address optional component inverted from free-format to structured fields},
year = {2026},
publisher = {RegLegBrief AI Hallucination Research},
note = {Hallucination finding Citation ID: RLB-F-INT-BIS-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-Q010},
url = {https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iso-20022-harmonisation-updated-2026/practitioners/lawyers/finding/INT-BIS-CPMI-INT-001-CPMI-ISO-20022-HARMONISATION-UPDATED-2026-v1-010/}
}