That is where many families get caught off guard.

A move abroad can complicate even the best-constructed U.S. plan. U.S. citizens and many long-term residents remain subject to U.S. tax on worldwide income even after leaving the country. At the same time, a new country of residence may impose its own income tax, wealth-transfer rules, reporting obligations, and succession laws. A trust that functions smoothly under U.S. law may be treated very differently abroad. An investment account that appears straightforward locally may create punitive U.S. tax consequences. An LLC that functions as a pass-through entity in the U.S. may be taxed as a corporation in a cross-border context. Documents that worked perfectly at home may no longer be sufficient in the jurisdiction where decisions are now being made.

The good news is that many of the most common problems can be avoided. In our experience, two of the most important steps are often the simplest: keep trust administration anchored in the United States through a U.S. trustee, and, where feasible, maintain your investment relationship with a U.S. money manager who understands the needs of U.S. taxpayers living internationally.

Why a move abroad can disrupt a U.S. estate and wealth plan

Many Americans heading overseas already have an estate plan, investment portfolio, and trust structure in place; a move to another country can change how each of those arrangements is treated and cause stress fractures in a structure that was solid for U.S. planning purposes.

The first issue is tax residence: many foreign jurisdictions may apply tax residency rules based not only on days spent in the country but also on where you maintain a home, where your family is based, or where your economic interests are centered. Once foreign tax residency is attached, the family may be subject to overlapping tax systems and additional compliance burdens.

The second issue is estate planning: Some countries apply forced heirship principles or default inheritance rules that may conflict with an American’s dispositive wishes. Others require local formalities for wills, powers of attorney, or healthcare directives. In some jurisdictions—especially civil law systems that do not readily accommodate common law trusts—trusts may not be recognized as U.S. families expect. As a result, trust terms may be challenged or prove ineffective and could cause double taxation.

The third issue is investment administration: Americans abroad frequently discover that opening or maintaining foreign investment accounts is harder than expected. Even when it is possible, the products offered may be poorly suited for a U.S. taxpayer, creating a mismatch between local convenience and U.S. tax efficiency.

Taken together, these issues make clear that international mobility should be treated as a coordinated planning process—not an afterthought.

The practical value of a U.S. trustee

If you already have trusts in place, one of the most important questions is whether those trusts will remain “U.S. trusts” - a defined tax term - for tax purposes after you or other key parties move abroad.

Under U.S. tax rules, a trust generally must satisfy both a “court test” and a “control test” to remain a U.S. trust. If trust administration is no longer effectively anchored in the U.S., or if substantial trust decisions are no longer controlled by U.S. persons, the trust can inadvertently become a “foreign trust” for U.S. tax purposes. This classification can trigger significant adverse consequences, including deemed recognition of gain in some cases, new reporting obligations, and less favorable treatment of future distributions.

When a U.S. trustee or powerholder is considering a move abroad or expatriation, it is important to identify potential U.S. successors who can step in to preserve the trust’s domestic status. However, designating an individual trustee or powerholder always involves the risk that changes in residence or citizenship could inadvertently compromise meeting the court and control tests: this is where a U.S. corporate trustee can be invaluable.

A U.S. corporate trustee can help preserve the domestic status of the trust, reduce the risk of inadvertent foreign trust conversion, maintain high-quality records, and coordinate with U.S. and non-U.S. advisors in a consistent way. Unlike an individual trustee, a U.S. corporate trustee is not likely to unknowingly jeopardize trust status by relocating overseas, renouncing citizenship, or becoming subject to foreign legal complications. Corporate trustees also bring continuity, institutional discipline, recordkeeping, and coordination capabilities that become especially important when families span jurisdictions.

There is also a strategic advantage in keeping trust oversight with an institution that understands how U.S. fiduciary tax rules interact with changing family residence. If a beneficiary moves to another jurisdiction that treats trust distributions differently, those consequences need to be managed as part of a broader plan. A U.S. corporate trustee can serve as the stable center of that plan.

Why remaining with a U.S. money manager may be the simplest path

Americans moving abroad may assume, or even be told, that they should shift their investments to a local institution in their new country of residence. In many cases, that change creates more problems than it solves.

One of the biggest risks is exposure to foreign pooled investment vehicles that may be classified as Passive Foreign Investment Companies, or PFICs, under U.S. tax law. PFIC rules are notoriously harsh—they can transform what appears to be an ordinary foreign fund investment into an inefficient structure marked by punitive tax treatment, interest charges, and complex annual reporting. In many cases, the compliance burden alone can outweigh the benefits of the investment.

These potential costs and pitfalls are what make maintaining a relationship with a U.S. money manager so valuable.

A U.S.-based advisor who is experienced in serving internationally-mobile Americans is far more likely to structure a portfolio with U.S. tax considerations front and center. That means understanding PFIC risk, coordinating with foreign tax advisors, and thinking carefully about what types of holdings are most appropriate when the client remains subject to the U.S. tax regime.

Maintaining U.S. asset management also provides the immeasurable benefit of simplicity. In contrast, the more accounts, platforms, and jurisdictions involved, the greater the likelihood of duplication, reporting errors, and fragmented advice. Keeping assets under the oversight of a U.S. money manager can preserve continuity with an advisor who already understands the client’s trusts, estate plan, liquidity needs, and tax profile. That continuity can be especially valuable when major life changes are happening all at once.

Local advice is, of course, still crucial. Local tax, legal, and residency issues are important, and local banking may be necessary for day-to-day living. But from a portfolio construction and U.S. tax-efficiency perspective, staying with a U.S. money manager often remains the more practical course.

Practical action steps before you move

The biggest mistake globally mobile families make is waiting until after the move to ask whether the structure still works. By then, the move may already have changed tax residence, triggered filing obligations, complicated trust administration, or introduced less efficient investment products.

The better approach is to simplify before complexity compounds. Review trusts before committing to a relocation; identify whether a trustee, protector, advisor, or powerholder change could affect U.S. trust status; and consider whether a U.S. corporate trustee should be appointed before the move. Evaluate whether the portfolio includes—or may soon include—foreign funds or other assets that are inefficient for a U.S. taxpayer. Update wills, powers of attorney, and healthcare directives so they work in both practical and legal terms. Coordinate among U.S. and local advisors so that immigration, tax, estate, and investment planning are all working from the same playbook.

For Americans moving abroad, these proactive steps can make a significant difference. International flexibility is possible, but it works best when the underlying financial architecture remains stable.

Final thought

Moving abroad can create exciting opportunities, but it should not come at the expense of tax efficiency, trust integrity, or administrative simplicity.

For U.S. families, the best cross-border planning is often not about reinventing everything, but rather about preserving what already works while adapting it carefully to a more international life. Keeping trust administration with a U.S. corporate trustee and maintaining a relationship with a U.S. money manager are two of the most effective ways to do exactly that.

If you are preparing for a move abroad, the right time to plan is before the move happens. With the right structure in place, you can pursue international flexibility without losing the benefits of a well-coordinated U.S. planning framework.

This material is not intended to constitute legal, tax, investment, or financial advice. Effort has been made to ensure that the material presented herein is accurate at the time of publication.

However, this material is not intended to be a full and exhaustive explanation of the law in any area or of all of the tax, investment or financial options available. The information discussed herein may not be applicable to or appropriate for every investor and should be used only after consultation with professionals who have reviewed your specific situation.