AI Labs · updated 2026-06-04 · methodology v2.1

Finding on 'Q010 Probe' for Claude Sonnet 4.6 with web search ON

RLB Citation ID: RLB-H-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q010-Sonnet46

What the RLB Specialist Panel found

Finding on 'Q010 Probe' for Claude Sonnet 4.6 with web search ON

Question (paraphrased to protect IP): A market briefing on the global fast payment system landscape was asked to include the proportion of fast payment systems operated by central banks versus private entities. The response correctly cited the 70+ global systems, 14 already cross-border, and 24 planning links — but falsely stated the ownership breakdown was not available in public CPMI sources, when the November 2023 CPMI speech by Tara Rice explicitly gives 40% central bank-operated and 35% privately operated.
AI's response: "A precise percentage breakdown of central bank vs. privately operated FPS is not enumerated in the public Brief 10 summaries available."
Regulator's text: Speech sp231115 (November 2023, Tara Rice): "70+ domestic fast payment systems currently operational globally"; "14 fast payment systems already enabling cross-border exchanges"; "24 systems planning linkages within five years"; "40% operated by central banks; 35% by private entities."
Why the AI went wrong: The model retrieved three statistics from the speech correctly but failed to retrieve the ownership breakdown that appears in the same source. The response asserted the ownership data was "not enumerated" in public sources — a false negative. The retrieval pipeline appears to have indexed the summary-level numeric data from the speech but dropped the ownership-breakdown figures, causing the model to report absence of data that is present in the accessible regulator record.
Cited source(s):
https://www.regulationtomorrow.com/eu/cpmi-issues-two-reports-offering-insigh... — Pretextual

Impact for this audience

The false-negative on ownership breakdown — asserting the 40%/35% figures were 'not enumerated in public sources' when they appear in the same speech the model successfully retrieved other statistics from — points to a partial-retrieval completeness failure. The retrieval pipeline indexed some sentences from the speech but dropped the ownership-breakdown paragraph. The model's self-check did not compare its 'not found' assertion against the full retrieved text of the already-confirmed source.

References — raw findings (per AI model)

RLB-H-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q010-Opus47 Claude Opus 4.7 (web search on)
RLB-H-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q010-Sonnet46 Claude Sonnet 4.6 (web search on)

This finding also affects

← Previous finding Finding on 'Q009 Probe' for Claude Sonnet 4.6 with web search ON

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-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q010-Sonnet46

Plain text Download

RegLeg Specialist Panel (2026). "Finding on 'Q010 Probe' for Claude Sonnet 4.6 with web search ON — AI Labs." Citation ID: RLB-H-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q010-Sonnet46. RegLegBrief AI Hallucination Research, published 2026-06-04. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-api-harmonisation-cross-border-2024/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-API-HARMONISATION-CROSS-BORDER-2024-v1-010--sonnet-46-websearch/

APA 7th edition Download

RegLeg Specialist Panel. (2026). Finding on 'Q010 Probe' for Claude Sonnet 4.6 with web search ON [Hallucination finding RLB-H-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q010-Sonnet46]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-api-harmonisation-cross-border-2024/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-API-HARMONISATION-CROSS-BORDER-2024-v1-010--sonnet-46-websearch/

Bluebook / OSCOLA (US + UK legal) Download

RegLeg Specialist Panel, Finding on 'Q010 Probe' for Claude Sonnet 4.6 with web search ON [RLB-H-INT-BIS-CPMI-API-HARMONISATION-CROSS-BORDER-2024-Q010-Sonnet46], RegLegBrief AI Hallucination Research (June 04, 2026), https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-api-harmonisation-cross-border-2024/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-API-HARMONISATION-CROSS-BORDER-2024-v1-010--sonnet-46-websearch/.

BibTeX Download

@misc{reglegbrief_RLB_H_INT_BIS_CPMI_API_HARMONISATION_CROSS_BORDER_2024_Q010_Sonnet46,
  author    = {RegLeg Specialist Panel},
  title     = {Finding on 'Q010 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-API-HARMONISATION-CROSS-BORDER-2024-Q010-Sonnet46},
  url       = {https://reglegbrief.com/regulators/j1/int/bis-cpmi/cpmi-api-harmonisation-cross-border-2024/whitepaper/finding/INT-BIS-CPMI-INT-001-CPMI-API-HARMONISATION-CROSS-BORDER-2024-v1-010--sonnet-46-websearch/}
}

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