Anglo-American Tax Frontiers

An AI-driven knowledge workspace for navigating the 2026 US-UK fiscal landscape.

Moving to or living in the United Kingdom as a US citizen means navigating one of the most complex cross-border tax environments in the world. With the historic abolition of the UK "non-dom" regime, the introduction of the new 4-Year Foreign Income and Gains (FIG) Regime, and sweeping US statutory adjustments, staying compliant while protecting your wealth requires instant access to ironclad, authoritative information.

To help cross-border wealth strategists, advisors, and expats maintain flawless compliance, we have built the Anglo-American Tax Frontiers Notebook—a secure digital media workspace pre-loaded with primary law, visual masterclass slide decks, clear infographics, and deep-dive audio overviews.

The Power of Q&A

The core feature of this notebook is your ability to run any custom query against the curated library. You can use the interactive chat interface to parse the US-UK Income Tax Treaty, the US-UK Estate & Gift Tax Treaty, HMRC Technical Manuals, and IRS 2026 Updates to generate tailored, hallucination-free summaries with complete technical accuracy.

Explore the Vault Using Custom Queries

You can query the notebook using natural, complex scenarios to instantly generate client checklists, compare regulations, or extract planning frameworks:

  • “Summarize how the new 10-out-of-20-years residence rule impacts global estate tax liability under the new LTR rules.”

  • “What specific arguments from the Anson v HMRC case can be used to defend the transparency of a US LLC?”

  • “Contrast the US tax reporting forms required for a UK SIPP versus a workplace pension scheme.”

What You Will Find Inside

This workspace consolidates an extensive library of primary legislation, international treaties, expert briefs, and strategic frameworks. The core materials integrated into this notebook include:

1. Primary Legislation & International Treaties

  • The Finance Act 2025 (UK): The legislative foundation outlining structural changes to UK income tax, capital gains tax (CGT), and inheritance tax (IHT).

  • US-UK Income Tax Treaty (2001): The official convention governing double taxation elimination, pension treatment, and residence conflicts.

  • US-UK Estate and Gift Tax Treaty (1980): Primary rules determining international estate taxation and jurisdiction over global assets.

  • US-UK Social Security Totalization Agreement: Guidance from the Social Security Administration (SSA) and IRS on avoiding dual-coverage for mobile employees and self-employed individuals.

2. Core UK Fiscal Regime Reforms (Post-April 2025)

  • The 4-Year Foreign Income and Gains (FIG) Regime: Official HMRC and LITRG documentation explaining the total abolition of the remittance basis and the mechanics of the new 4-year qualifying residence exemption.

  • The Temporary Repatriation Facility (TRF): Detailed parameters from Deloitte detailing the 3-year window allowing former remittance basis users to remit historic offshore funds at a flat 12% or 15% rate.

  • Long-Term Resident (LTR) Inheritance Tax Rules: Technical insights from Saffery and Royal London on the structural pivot from a domicile-based to a residence-based IHT model (defining the 10-out-of-20-years LTR threshold).

  • Trust and Corporate Overhauls: Legal breakdowns from Birketts on Family Investment Companies (FICs), Family Limited Partnerships (FLPs), and the expiration of excluded property trust protections for incoming long-term residents.

  • APR & BPR Reforms: Government policy papers detailing updates to Agricultural Property Relief and Business Property Relief.

3. US Federal Tax & Expat Compliance (2026 Updates)

  • 2026 Tax Brackets & Statutory Adjustments: The latest Tax Foundation data incorporating amendments from recent federal legislation (such as the One Big Beautiful Bill Act), including the permanently adjusted individual income brackets and the $40,400 State and Local Tax (SALT) deduction cap.

  • 2026 Foreign Earned Income Exclusion (FEIE): IRS inflation adjustments confirming the increase of the FEIE ceiling to $132,900.

  • Cross-Border Core Guides: A comprehensive collection of structural frameworks covering the tax drag of US-domiciled ETFs in the UK, the severe IRS reporting penalties under Passive Foreign Investment Company (PFIC) rules (Form 8621), the asymmetric treatment of UK pension lump sums, and the hidden US tax exposure of UK ISAs.

Core Cross-Border Frontiers Addressed Inside

Open the notebook to instantly review and query definitive, source-backed analysis on the most critical fiscal questions facing US expats in the UK today:

🌐 The New 4-Year FIG Regime

Effective 6 April 2025, the UK's legacy non-domiciled framework and the remittance basis have been completely dismantled. In its place stands the 4-Year Foreign Income and Gains (FIG) Regime. Learn how individuals within their first four years of UK residence can bring foreign income and gains into the UK completely tax-free —and discover the strict "arising basis" rules that apply the moment that window closes.

📉 The US LLC Opaque Trap

There is a severe structural mismatch between how the US and UK classify Limited Liability Companies. While the IRS permits pass-through tax treatment, HMRC's default position is that a US LLC is treated as an opaque entity (akin to a corporation). Query the notebook's pre-loaded briefs detailing how this mismatch triggers double taxation, and review the landmark case law (Anson v HMRC) used to defend corporate transparency.

🏦 The 25% Pension Commencement Lump Sum (PCLS)

Taking up to 25% of your pension pot tax-free is a staple of UK retirement planning. However, the IRS does not recognize this tax-free treatment and views it as fully taxable ordinary income. Review our pre-compiled guides on why this exposure prevents you from using Foreign Tax Credits and search the included multi-year distribution frameworks designed to minimize tax bracket impact.

📜 Post-Reform Trust & Estate Planning

The UK has officially pivoted from a domicile-based Inheritance Tax (IHT) system to a residence-based system. Use the workspace to review the core legal analysis demonstrating how the US-UK Estate and Gift Tax Treaty provides an extraordinary three-year window post-arrival for US citizens to establish trusts that remain permanently shielded from UK IHT.

🔍 Instant Fiscal Clarity. Zero Noise.

Stop sorting through scattered PDFs, outdated blog posts, and conflicting online articles. The Anglo-American Tax Frontiers Notebook organizes your cross-border educational journey into a single, streamlined multimedia ecosystem.

By anchoring every response directly within curated, authoritative guidelines—ranging from the Internal Revenue Service (IRS) and HM Revenue & Customs (HMRC) statutes to primary legislation like the Finance Act 2025—this tool allows you to analyze complex, dual-status tax rules efficiently while minimizing errors and hallucinations.

Choose Your Access Pass

Gain instant, unrestricted access to the complete digital repository and interactive Q&A interfaces:

  • Monthly Access: $65 / month (does NOT renew automatically)

    • Best for: Short-term research, specific seasonal filing questions, or immediate cross-border compliance planning.

  • Annual Access: $499 / year — Best Value

    • Save over 35% compared to the monthly rate. Continuous access to all updates throughout the 2026 tax year, keeping your financial strategies perfectly aligned with ongoing regulatory adjustments and new IRS enforcement guidelines.

NOTE: The Anglo-American Tax Frontiers notebook is hosted on Google’s NotebookLM platform. You need a Google account to access it. If you do not have one, you can create one for free at accounts.google.com/signup.

1 month Access - $65
Annual Access - $499