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AI Labs · Last updated 7 Jun 2026 · methodology v2.1 · Hallucination Register

Finding on 'Q002 Probe' for Claude Sonnet 4.6 with web search ON

RLB Citation ID: RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q002-Sonnet46
What the RLB Specialist Panel found

Finding on 'Q002 Probe' for Claude Sonnet 4.6 with web search ON

  • Question (paraphrased to protect IP): What does Section IV.3 of the 2025 OECD Merger Review Recommendation establish as the hierarchy for acceptable remedies in merger proceedings, and what is the priority ordering within the structural remedies tier?
  • AI's response: "Within structural remedies, there is a further internal preference ordering:, Upfront / 'fix-it-first' divestitures...rank highest..., Divestiture commitments with an approved buyer pool and a trustee mandate as backstop rank second., 'Crown jewel' or ring-fenced asset packages...rank third."
  • Regulator's text: Section IV.3 states: "Prioritise structural remedies over behavioural ones and, for structural remedies, prioritise the divestiture of standalone businesses."
  • Why the AI went wrong: Section IV.3 establishes a two-level preference: structural over behavioural, and standalone-business divestiture as the preferred structural form. The model elaborated this into a three-tier internal ranking, upfront/fix-it-first divestiture, buyer pool with trustee backstop, crown jewel packages, that maps onto common EU and US merger remedy practice but does not appear in the 2025 OECD Recommendation's text. The model substituted a practitioner-familiar remedy taxonomy drawn from other jurisdictions' frameworks for the Recommendation's simpler, less-prescriptive hierarchy, and presented the elaborated ranking as the OECD standard.
  • Cited source(s):
Impact for this audience

The three-tier internal remedy ranking the model produced maps precisely onto EU Merger Regulation remedy practice and US DOJ/FTC remedy convention — frameworks heavily represented in training. The OECD Recommendation's simpler two-level preference appears insufficiently weighted to override the more detailed framework when both are plausibly relevant. This implicates retrieval ranking (primary text vs. adjacent-jurisdiction commentary) and calibration (schema-elaboration confidence when the retrieved content does not support the elaboration).

References — raw findings (per AI model)
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Cite this finding

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.

RLB Citation ID: RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q002-Sonnet46
Plain text Download 
RegLeg Specialist Panel (2026). "Finding on 'Q002 Probe' for Claude Sonnet 4.6 with web search ON — AI Labs." Citation ID: RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q002-Sonnet46. RegLegBrief AI Hallucination Research, published 2026-06-07. https://reglegbrief.com/regulators/j1/INT/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/whitepaper/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-002--sonnet-46-websearch/
APA 7th edition Download 
RegLeg Specialist Panel. (2026). Finding on 'Q002 Probe' for Claude Sonnet 4.6 with web search ON [Hallucination finding RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q002-Sonnet46]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/INT/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/whitepaper/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-002--sonnet-46-websearch/
Bluebook / OSCOLA (US + UK legal) Download 
RegLeg Specialist Panel, Finding on 'Q002 Probe' for Claude Sonnet 4.6 with web search ON [RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q002-Sonnet46], RegLegBrief AI Hallucination Research (June 07, 2026), https://reglegbrief.com/regulators/j1/INT/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/whitepaper/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-002--sonnet-46-websearch/.
BibTeX Download 
@misc{reglegbrief_RLB_H_INT_OECD_OECD_MERGER_REVIEW_RECOMMENDATION_2025_Q002_Sonnet46,
  author    = {RegLeg Specialist Panel},
  title     = {Finding on 'Q002 Probe' for Claude Sonnet 4.6 with web search ON},
  year      = {2026},
  publisher = {RegLegBrief AI Hallucination Research},
  note      = {Hallucination finding Citation ID: RLB-H-INT-OECD-OECD-MERGER-REVIEW-RECOMMENDATION-2025-Q002-Sonnet46},
  url       = {https://reglegbrief.com/regulators/j1/INT/OECD/OECD-MERGER-REVIEW-RECOMMENDATION-2025/whitepaper/finding/INT-OECD-INT-001-OECD-MERGER-REVIEW-RECOMMENDATION-2025-v1-002--sonnet-46-websearch/}
}
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