Currency and Cross-Border Portfolio Structuring for US Taxpayers Living in the UK

Written by Ben Lightfoot, CFP™

A practical framework for holding cash, investing efficiently, and reducing avoidable currency and tax conflicts

If you’re a US taxpayer living in the UK, three decisions frequently influence portfolio outcomes:

1. Matching short-term cash to the currency you spend
2. Building long-term portfolios in structures that may help avoid common US and UK tax pitfalls
3. Being intentional about where currency risk appears across equities and bonds

This paper outlines a framework that may help make currency decisions based on purpose and time horizon, rather than attempting to predict GBP/USD movements.

Starting with the basics: what currency is for

Currency exposure influences the stability and predictability of your financial life. It can help or hinder depending on where it appears, so it’s helpful to connect currency choices to the purpose of the money involved.

Instead of asking “Will the dollar rise or fall?”, a useful starting point is asking: “What is this money for, and when will I need it?”

A clear way to think about your finances is through three buckets:

1. Spend and live (today through 12–24 months)
2. Grow (long-term investing, usually 5+ years)
3. Stabilize (the part of the portfolio meant to provide reliability for spending and reduce overall volatility)

Each bucket tends to have its own currency considerations.

Bucket 1: Short-term money should match your spending currency

Near-term cash is the foundation of day-to-day stability. If you live in the UK and your costs are in pounds, then holding your cash and near-term savings in GBP may help keep things steadier. It also may help avoid unpleasant surprises if exchange rates move abruptly.

What this may achieve:

• More stable purchasing power
• Fewer surprises caused by short-term currency moves
• A clear separation between money for living and money for investing

Bucket 2: Long-term investing – it’s about structure, not currency forecasts

Once you move beyond short-term spending, the priority often shifts from “avoid FX volatility” to “invest in a structure that stays diversified and efficient for a US taxpayer living in the UK.”

The structural cornerstone: avoid tax traps

US‑domiciled funds with UK‑reporting status is often considered a practical and efficient approach for several reasons:

• They avoid punitive US PFIC treatment associated with non-US funds
• They simplify reporting across both tax systems
• They can provide broader, low-cost access to global markets

Practical platform considerations

Whether an account is held at a US custodian or UK custodian may be less important than ensuring it can hold appropriate underlying funds. This may also influence options for bonds, particularly if you want the ability to hold GBP-denominated instruments for near-term UK spending needs.

Growth assets (equities): diversify globally and generally stay unhedged

For long-term investors, global equities are usually held unhedged. Over long time horizons, returns tend to be driven by company fundamentals rather than currency movements, and hedging introduces cost and complexity.

A helpful distinction:

• A fund priced in GBP does not mean it is hedged to GBP
• Most global equity funds simply report their value in GBP while still holding multinational companies whose earnings come from many underlying currencies.

The takeaway: Currency exposure is part of owning global equities, and this approach often works well for long-term investors who prioritize global diversification.

Bucket 3: Stability and protection (the defensive allocation)

Bonds support spending reliability and help reduce overall portfolio volatility. Because stability is the goal, currency exposure inside fixed income deserves specific attention.

A practical framework for US taxpayers involves three common approaches:

Approach 1: GBP-denominated individual bonds (taxable accounts)

• Useful for: Shorter-term GBP spending needs where stability is paramount
• Why: They offer a clear currency match and avoid PFIC exposure because they are direct holdings rather than funds

Approach 2: Global bond funds using US-domiciled ETFs with UK reporting status (taxable accounts)

• Useful for: Longer-term defensive allocations not tied to specific near-term liabilities
• Why: They offer diversification across issuers, maturities, and credit quality. Currency exposure is present, but the purpose here is long-term resilience rather than short-term stability

Approach 3: GBP bond funds (tax-sheltered accounts only)

• Useful for: Investors who want GBP currency matching within diversified bond funds
• Why: These funds are typically only appropriate inside accounts that shield them from US PFIC rules, such as US IRAs, Roth IRAs, and UK pensions

Each approach has strengths, and the more appropriate choice often depends on the role those bonds are expected to play and the available account structures.

Pulling it together: how to hold both GBP and USD deliberately

Most US expats end up holding meaningful amounts in both currencies. This can be healthy diversification if the mix is intentional, which often looks something like this:

• Cash and near-term reserves: Mostly GBP
• Global equities: Diversified and typically unhedged
• Bonds for near-term GBP needs in taxable accounts: GBP individual bonds
• Bonds for long-term stability in taxable accounts: Global bond funds (US ETFs with UK reporting status)
• GBP bond funds: Only inside tax-sheltered accounts

This can create a system that is purposeful, coherent, and straightforward to manage over time

Common questions that create confusion

Q: If I invest in the US, the UK won’t tax it?

A: In cross-border situations, account location typically does not determine cross-jurisdiction taxation. Underlying fund structure often matters more for tax treatment.

Q: Should I hedge all my equity exposure because I spend in GBP?

A: Many global funds priced in GBP are not actually hedged; they simply report values in GBP. For long-term investors, unhedged global equities may provide more reliable outcomes.

Q: Are GBP bonds always safest if I live in the UK?

A: They may be well-suited for near-term GBP spending needs in taxable accounts, or for longer-term needs when held in tax-sheltered accounts. They are not automatically optimal for all situations, particularly in taxable accounts where global diversification or PFIC considerations may apply.

Practical next steps

Questions that may help inform this framework:

1. What GBP spending needs might you have over the next 12 – 24 months?

This may help inform appropriate GBP cash reserves.

2. Which accounts are taxable, and what fund structures work efficiently within both tax systems?

This consideration may help identify suitable investment options and prevent potential surprises.

3. What role is your defensive allocation expected to play, and which account types are available?

Near-term stability considerations in taxable accounts may suggest GBP individual bonds. Longer-term resilience in taxable accounts may suggest global bond funds. GBP matching with diversification may suggest GBP bond funds in tax-sheltered accounts where available.

Clarifying these elements may help make currency decisions more straightforward to navigate.

The Legal Stuff

• The information contained herein is subject to copyright with all rights reserved. The document may not be copied, forwarded or otherwise distributed, in whole or in part, to any other party without our written consent.
• Nothing in this document constitutes investment, tax or any other type of advice and should not be construed as such.
• MASECO is not a tax specialist and we recommend that anyone considering investing seeks their own tax advice.
• The views expressed in this article do not necessarily reflect the views of MASECO as a whole or any part thereof.
• This document is provided for information purposes only and is not intended to be relied upon as a forecast, research or investment advice.
• This document does not constitute a recommendation, offer or solicitation to buy or sell any products or to adopt an investment strategy.

 Risk Warnings:

• All investments involve risk and may lose value. The value of your investment can go down depending upon market conditions and you may not get back the original amount invested.
• Your capital is always at risk.
• Fluctuation in currency exchange rates may cause the value of an investment and/or a portfolio to go up or down.
• Alternative strategies involve higher risks than traditional investments, such as speculative investment techniques, which can magnify the potential for investment loss or gain.
• Any impact from the actual or speculative tax changes contained in this document will depend on the individual circumstances of each client and may be subject to change in the future.
• Information about potential tax benefits is based on our understanding of current tax law and practice and may be subject to change. The levels and bases of, and reliefs from, taxation is subject to change.  The tax treatment depends on the individual circumstances of each individual and may be subject to change in the future.
• Certain products which may be used within a portfolio in order to give exposure to particular investment strategies may not be regulated in the UK and therefore will not have the benefit of the protections afforded by the UK regulatory regime.

 Performance:

• Past performance is not a reliable indicator of future results.
• No assurance or guarantee can be given that any target return will be achieved.
• Illustrations of potential risk or return are illustrative only and do not necessarily reflect possible actual maximum loss or gain.

MASECO LLP is authorised and regulated by the Financial Conduct Authority for the conduct of investment business in the UK and is registered with the US Securities and Exchange Commission as a Registered Investment Advisor.

Nothing in this document constitutes investment, tax or any other type of advice and should not be construed as such.

MASECO is not a tax specialist and we recommend that anyone considering investing seeks their own tax advice. MASECO LLP is authorised and regulated by the Financial Conduct Authority for the conduct of investment business in the UK and is registered with the US Securities and Exchange Commission as a Registered Investment Advisor.