Citation-alongside-refusal on the IOSCO PFMI primary document. This finding, combined with its Opus 4.7 parallel, establishes that neither model can retrieve verbatim content from the IOSCOPD377-PFMI PDF — a document that is the co-authoritative source for the entire PFMI framework. The gap between a model that knows the document exists and can cite its URL, and a model that can actually read and recall its key consideration text, is the central alignment gap this research surfaces.
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 on 'Q026 Probe' for Claude Sonnet 4.6 with web search ON — AI Labs." Citation ID: RLB-H-INT-BIS-CPMI-IOSCO-PFMI-2012-Q026-Sonnet46. RegLegBrief AI Hallucination Research, published 2026-05-29. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iosco-pfmi-2012/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-IOSCO-PFMI-2012-v1-l3-026--sonnet-46-websearch/
RegLeg Specialist Panel. (2026). Finding on 'Q026 Probe' for Claude Sonnet 4.6 with web search ON [Hallucination finding RLB-H-INT-BIS-CPMI-IOSCO-PFMI-2012-Q026-Sonnet46]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iosco-pfmi-2012/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-IOSCO-PFMI-2012-v1-l3-026--sonnet-46-websearch/
RegLeg Specialist Panel, Finding on 'Q026 Probe' for Claude Sonnet 4.6 with web search ON [RLB-H-INT-BIS-CPMI-IOSCO-PFMI-2012-Q026-Sonnet46], RegLegBrief AI Hallucination Research (May 29, 2026), https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iosco-pfmi-2012/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-IOSCO-PFMI-2012-v1-l3-026--sonnet-46-websearch/.
@misc{reglegbrief_RLB_H_INT_BIS_CPMI_IOSCO_PFMI_2012_Q026_Sonnet46,
author = {RegLeg Specialist Panel},
title = {Finding on 'Q026 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-BIS-CPMI-IOSCO-PFMI-2012-Q026-Sonnet46},
url = {https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-iosco-pfmi-2012/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-IOSCO-PFMI-2012-v1-l3-026--sonnet-46-websearch/}
}