un-tariff grounds every calculation, rule, and guide in primary sources published by CBP, USITC, the Federal Register, and the U.S. Supreme Court. This page lists the exact publications we consult and link to throughout the site, with citation strings and last-verified dates.
Official CBP bulletin announcing the launch of Phase 1 of the CAPE refund system on April 10, 2026. This is the primary authority for CAPE activation date and initial filing rules.
CSMS #68315804 (2026-04-10)CBP bulletin issued April 13, 2026 clarifying CAPE validation rules after the initial Phase 1 launch. Governs entry-number format, file encoding, and duplicate-detection logic.
CSMS #68340863 (2026-04-13)The authoritative ACE technical specification for entry summary record layouts, field definitions, and validation codes. Revision 108 is the current version governing CAPE-era filings (Rev 107, 2025-09-03 retained as prior revision).
CBP CATAIR Entry Summary Create/Update Rev 108 (2025-09-09)The standard CBP entry summary form. un-tariff maps every field in your ACE export to the Form 7501 schema when classifying entries for IEEPA eligibility and CAPE inclusion.
CBP Form 7501 (2026-02)CBP publishes overpayment interest rates quarterly under 19 CFR 24.3a. un-tariff walks these rates daily from the duty-payment date to estimate accrued interest on each CAPE claim.
19 CFR 24.3a (CBP quarterly overpayment rate)The official US HTS, including Chapter 99 subheadings 9903.01.xx and 9903.02.xx that define which imports were subject to IEEPA tariffs. un-tariff's IEEPA HTS registry is derived from this publication.
USITC HTS 2026 Rev 5 (2026-04-18)The February 20, 2026 Supreme Court opinion holding that IEEPA tariffs imposed by executive order exceeded presidential authority. This ruling is the legal foundation for every refund claim un-tariff helps prepare.
SCOTUS 24-1287 Learning Resources v. Trump (2026-02-20)The Federal Register publication of the April 2, 2025 executive order imposing IEEPA reciprocal tariffs, including the country-specific rate annex that maps HTS subheadings to tariff rates. un-tariff uses this to confirm which entries are in scope.
EO 2025-06063 Reciprocal Tariff (2025-04-02)The canonical publisher of executive orders, agency rules, and notices. All IEEPA-related executive orders and CBP rulemaking cited by un-tariff are sourced from federalregister.gov.
Federal Register (federalregister.gov)The Automated Commercial Environment portal is where importers upload CAPE Declaration CSV files to claim IEEPA refunds. un-tariff generates files validated against CBP's ACE submission rules.
ACE Portal (ace.cbp.dhs.gov)If you spot a stale or missing citation, email us at support@un-tariff.com. See also the methodology page for how these sources feed into calculations.