How is the 2025 OECD Merger Review Recommendation (OECD/LEGAL/0333) structured, and which subject-matter areas were added in the 2025 revision relative to the superseded 2005 version?
The model generated a six-section architecture for an instrument that has five, inserting "International Co-operation" and "Monitoring" as standalone operative sections. The 2025 Recommendation does not structure those topics as separate sections; the model appears to have reconstructed the document's architecture from merger-review convention and prior OECD instruments, both of which commonly present monitoring and cooperation as dedicated sections, rather than from the 2025 revision's actual text.
The structural fabrication implicates the training-data representation of the 2025 revision specifically: the model's schema for this instrument appears to be drawn from pre-revision OECD materials or merger-review convention, neither of which reflects the 2025 Recommendation's five-section architecture. The retrieval layer (web search active) did not surface or weight the 2025 primary text sufficiently to override the reconstruction, pointing to a retrieval-ranking gap for recently-revised OECD soft-law instruments.
How is the 2025 OECD Merger Review Recommendation (OECD/LEGAL/0333) structured, what does each operative section address, and which subject-matter areas did the 2025 revision add that were absent from the 2005 version?
The model generated an identical structural error to Claude Opus 4.7 with web search on the same question, a six-section architecture with "Cross-Jurisdictional Co-operation" and "Monitoring and Review" inserted as standalone operative areas. The near-exact convergence across two configurations that differ substantially in size and post-training tuning, both with web search active, points to a shared training-data gap on the 2025 revision's structure rather than a configuration-specific artefact. The retrieval layer did not surface or weight the primary text sufficiently to correct the reconstruction.
Near-exact convergence with Claude Opus 4.7 with web search on the same structural fabrication — a six-section architecture, with the same inserted section names — across configurations that differ substantially in model size, post-training tuning, and retrieval behaviour. The shared error points to a training-data gap on the 2025 Recommendation's structure rather than a model-specific artefact, and confirms the retrieval layer is not compensating for the gap in either configuration.
Two AI tools produced a six-section structural account of the 2025 Recommendation that inserted 'International Co-operation' and 'Monitoring' as standalone operative RECOMMENDS clauses and omitted Section V, ex-post assessment of merger decisions and remedies, entirely. A legal team at a mainboard issuer that uses this account to draft internal M&A policy or a board-level regulatory mapping document produces a governance framework calibrated to a phantom architecture: one operative section that does not exist, and a missing obligation that does.
The deliverable will not flag that adherent-state authorities can revisit completed transactions under Section V, leaving the firm without the post-closing risk tracking that the 2025 revision requires. Because the AI's account was internally coherent and thematically plausible, the error will survive internal review unless a lawyer independently verifies OECD/LEGAL/0333.
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 (2026). "Finding#1, Invented cross-border cooperation section; Section V dropped — Mainboard Issuers × Legal — International / Multilateral." Citation ID: RLB-F-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001. RegLegBrief AI Hallucination Research, published 2026-06-11. https://reglegbrief.com/regulators/j1/int/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/sectors/mainboard_issuers/legal/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-001/
RegLeg Specialist Panel. (2026). Finding#1, Invented cross-border cooperation section; Section V dropped [Hallucination finding RLB-F-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/int/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/sectors/mainboard_issuers/legal/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-001/
RegLeg Specialist Panel, Finding#1, Invented cross-border cooperation section; Section V dropped [RLB-F-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001], RegLegBrief AI Hallucination Research (June 11, 2026), https://reglegbrief.com/regulators/j1/int/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/sectors/mainboard_issuers/legal/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-001/.
@misc{reglegbrief_RLB_F_INT_OECD_OECD_MERGER_REVIEW_RECOMMENDATION_2025_Q001,
author = {RegLeg Specialist Panel},
title = {Finding#1, Invented cross-border cooperation section; Section V dropped},
year = {2026},
publisher = {RegLegBrief AI Hallucination Research},
note = {Hallucination finding Citation ID: RLB-F-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q001},
url = {https://reglegbrief.com/regulators/j1/int/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/sectors/mainboard_issuers/legal/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-001/}
}
Every finding on this page compares an AI subject's account of the rule against the regulator's verbatim text from the regulator's own portal. Both are linked. Each delta, its root causes, and impact analysis are documented and published with immutable Citation IDs.