AI subject tested: Claude Sonnet 4.6 (web search on)
Question (paraphrased): Does a portfolio maturity constraint apply to direct US Treasury securities held in an FCM's customer segregated account under Regulation 1.25, and if so, what is the dollar-weighted average maturity limit?
AI response:
"The 2024 amendments do not impose a new dollar-weighted average maturity (DWAM) standard or a maximum remaining-maturity cap specifically on direct U.S. Treasury obligations...No DWAM standard or individual-maturity cap found in the 2024 amendments applies to that category."
Regulator verbatim text:
"The dollar-weighted average of the time-to-maturity of the portfolio may not exceed 24 months. This limit excludes government money market funds, Treasury ETFs, and foreign sovereign debt from the calculation."
Failure mode: inference_drift
Substrate document: p_03_REGULATION_17_CFR_1_25_b__3__iv____dollar_weighted_download.pdf
This finding documents a confirmed hallucination by Claude Sonnet 4.6 (web search on) on a probe of the regulation. The model's response was tested against the regulator's verbatim primary text and classified as inference_drift. Full per-finding context is available via the linked Citation ID.
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). "Does a portfolio maturity constraint apply to direct US Treasury securities held in an FCM's customer segregated account — AI Labs." Citation ID: RLB-H-US-CFTC-FCM-DCO-CUSTOMER-FUNDS-INVESTMENTS-REG-1-25-2024-Q002-Sonnet46. RegLegBrief AI Hallucination Research, published 2026-06-07. https://reglegbrief.com/regulators/j3/us/cftc/fcm-dco-customer-funds-investments-reg-1-25-2024/whitepaper/finding/US-CFTC-US-001-FCM-DCO-CUSTOMER-FUNDS-INVESTMENTS-REG-1-25-2024-v1-002--sonnet-46-websearch/
RegLeg Specialist Panel. (2026). Does a portfolio maturity constraint apply to direct US Treasury securities held in an FCM's customer segregated account [Hallucination finding RLB-H-US-CFTC-FCM-DCO-CUSTOMER-FUNDS-INVESTMENTS-REG-1-25-2024-Q002-Sonnet46]. RegLegBrief AI Hallucination Research. https://reglegbrief.com/regulators/j3/us/cftc/fcm-dco-customer-funds-investments-reg-1-25-2024/whitepaper/finding/US-CFTC-US-001-FCM-DCO-CUSTOMER-FUNDS-INVESTMENTS-REG-1-25-2024-v1-002--sonnet-46-websearch/
RegLeg Specialist Panel, Does a portfolio maturity constraint apply to direct US Treasury securities held in an FCM's customer segregated account [RLB-H-US-CFTC-FCM-DCO-CUSTOMER-FUNDS-INVESTMENTS-REG-1-25-2024-Q002-Sonnet46], RegLegBrief AI Hallucination Research (June 07, 2026), https://reglegbrief.com/regulators/j3/us/cftc/fcm-dco-customer-funds-investments-reg-1-25-2024/whitepaper/finding/US-CFTC-US-001-FCM-DCO-CUSTOMER-FUNDS-INVESTMENTS-REG-1-25-2024-v1-002--sonnet-46-websearch/.
@misc{reglegbrief_RLB_H_US_CFTC_FCM_DCO_CUSTOMER_FUNDS_INVESTMENTS_REG_1_25_2024_Q002_Sonnet46,
author = {RegLeg Specialist Panel},
title = {Does a portfolio maturity constraint apply to direct US Treasury securities held in an FCM's customer segregated account},
year = {2026},
publisher = {RegLegBrief AI Hallucination Research},
note = {Hallucination finding Citation ID: RLB-H-US-CFTC-FCM-DCO-CUSTOMER-FUNDS-INVESTMENTS-REG-1-25-2024-Q002-Sonnet46},
url = {https://reglegbrief.com/regulators/j3/us/cftc/fcm-dco-customer-funds-investments-reg-1-25-2024/whitepaper/finding/US-CFTC-US-001-FCM-DCO-CUSTOMER-FUNDS-INVESTMENTS-REG-1-25-2024-v1-002--sonnet-46-websearch/}
}
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.