Avoiding $52,500 of U.S. Tax Through Pension Planning

The Challenge

A non-U.S. individual approached Expat Tax Professionals before moving from Singapore to the United Kingdom. She had recently become eligible to withdraw approximately $175,000 from a U.S. 401(k) without an early-distribution penalty and expected to qualify for the UK's four-year Foreign Income and Gains (FIG) regime.

The opportunity turned on a critical distinction in the U.S.-UK income tax treaty. Periodic pension payments are taxable only in the country of residence, while lump-sum payments from a U.S. plan remain taxable only in the United States. Under U.S. domestic law, the client's withdrawals could otherwise face 30% gross withholding. A single full withdrawal could therefore generate approximately $52,500 of U.S. tax.

Our Approach

ETP analyzed three competing interpretations of the treaty's undefined term "lump sum," including the U.S. statutory definition, the treaty's anti-abuse purpose and HMRC guidance issued in March 2025. HMRC indicated that payments of 20% or more will often be lump sums, but also recognized that five regularly scheduled payments may instead be periodic when the arrangement is considered as a whole.

We recommended equal monthly withdrawals over five UK tax years, with 20% of the original account balance withdrawn each year. Regular payment dates and consistent amounts provided strong support for periodic treatment under the treaty. Once UK resident, the client would submit Form W-8BEN to the plan administrator to claim treaty exemption from U.S. withholding and claim FIG relief on her UK self-assessment returns.

Creating Additional Value

The first four annual tranches - approximately $140,000, or 80% of the account - should fall within the FIG window and be exempt from both U.S. tax under the treaty and UK tax under the FIG regime. The fifth-year tranche of approximately $35,000 would fall outside FIG and be taxable in the UK, but remain exempt from U.S. tax.

This balanced strategy avoided the more aggressive approach of liquidating the entire account during the four-year FIG period, which could be challenged as a lump sum or as an attempt to achieve the precise double non-taxation that the treaty provision was designed to prevent. Aligning the withdrawal pattern with HMRC's published factors made the treaty position more defensible.

The Result

By coordinating U.S. treaty treatment with the UK's temporary FIG regime, ETP developed a practical path to draw down the entire 401(k) while limiting tax to the final 20% tranche. Our strategy helped the client:

• Save approximately $52,500 in potential U.S. withholding tax;

• Withdraw approximately $140,000 during the FIG period without U.S. or UK tax;

• Keep every scheduled withdrawal exempt from U.S. tax under the treaty; and

• Limit UK taxation to the final approximately $35,000 tranche while implementing the required U.S. and UK reporting.