Operating a business across the US and UK requires navigating two of the world’s most complex corporate tax regimes simultaneously. Entity structure, transfer pricing, withholding taxes, treaty access, and compliance across both jurisdictions demand coordinated expertise — not two separate advisers working in isolation.
We advise businesses from early-stage structuring through to complex international group tax, covering corporate tax compliance, advisory, and strategic planning for both US and UK entities.
Who We Serve
- UK companies with US shareholders, directors, or operations
- US corporations expanding into the UK
- LLCs with UK resident members
- Entrepreneurs choosing between US LLC, UK Ltd, or dual-entity structures
- Investment funds with US and UK investors
- Privately held groups with cross-border intercompany transactions
Tax Forms We Prepare & File
US Business Filings
- Form 1120 — US Corporation Income Tax Return
- Form 1120-S — US S-Corporation Return
- Form 1065 — US Partnership Return (including multi-member LLCs)
- Form 5471 — Information Return for US persons with interests in foreign corporations (including UK companies)
- Form 8865 — Return of US persons with respect to certain foreign partnerships
- Form 8858 — Foreign Disregarded Entity information
- Form 8833 — Treaty-based position disclosure
- Form W-8BEN-E — Certificate of foreign status for entities, for withholding and treaty purposes
- Form W-9 — US person certification for US-sourced payments
UK Business Filings
- CT600 — UK Corporation Tax Return, including R&D relief claims, group relief, and loss provisions
- VAT Returns — Under Making Tax Digital (MTD), including registration, returns, and reclaim
- P11D — Benefits-in-kind reporting for directors and employees
- PAYE & RTI — Payroll processing and HMRC Real Time Information submissions
- CIS Returns — Construction Industry Scheme compliance
- Capital Gains reporting — 60-day UK residential property CGT report
Entity Structure & the LLC Problem
The single most consequential early decision for a US entrepreneur in the UK is entity structure. A US LLC is treated as a transparent entity by the IRS but may be treated as opaque by HMRC — creating a “hybrid mismatch” that, if unaddressed, can result in both income and corporate tax applying simultaneously with no treaty relief.
We advise on entity selection from day one, considering:
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- Branch vs. subsidiary structure
- US-UK treaty access for each entity type
- VAT registration and group treatment
- Director and shareholder tax implications
Transfer Pricing
Any intercompany transaction between connected US and UK entities — management charges, loans, IP licences, service fees — must be priced on arm’s length terms and documented. Both the IRS and HMRC have increased scrutiny of thin-capitalISAtion and profit-shifting. We prepare transfer pricing documentation and implement defensible policies.
Penalties for Non-Compliance
- Form 5471 / 8865 / 8858: $10,000 per form per year, automatic on late or non-filing
- CT600 late filing: £100 automatic, escalating to £1,000 and 10% of tax after 12 months
- VAT penalties: Surcharge and penalty regime under the new MTD penalty framework
- Transfer pricing adjustments: Primary and corresponding adjustments, plus penalties and interest
Frequently Asked Questions
My UK company paid UK corporation tax. Does the US still tax me?
If you are a US person with an interest in a UK company, there are US reporting and potentially US tax implications regardless of the UK tax paid. This depends on the entity type, your ownership level, and whether the company is a Controlled Foreign Corporation (CFC). We clarify your exact position.
Do I need to register for VAT?
UK VAT registration is compulsory once turnover exceeds the registration threshold (currently £90,000 for 2024/25). It may be advantageous to register voluntarily before that. We advise on the right timing and structure for your business.
Related Services
Get your business structure right from the start. Book a consultation with our corporate tax specialists.