Forced Heirship and Trusts: Which Jurisdictions Hold Up Against Heir Claims

Anyone comparing forced heirship trusts jurisdictions eventually reaches the same uncomfortable point: a trust is a private arrangement, but inheritance rules are public policy. Civil-law countries reserve part of an estate for close relatives, while several common-law seats have written statutes that tell their courts to ignore those reserved claims. The two approaches meet head-on when a settlor, the trust assets, the trustee and the heirs sit in different places. This guide explains where the clash comes from, how each camp reasons, and where Switzerland stands between them.

It is general information, not advice. The answer for a given family depends on where the settlor lived, which assets were transferred, where the heirs live and which court ends up deciding.

What forced heirship means in practice

Forced heirship, or reserved shares, is the part of an estate that the law sets aside for specified relatives whatever the deceased wrote in a will. In Switzerland the rule sits in the Civil Code. Article 471 CC fixes the reserve at half of the statutory inheritance entitlement, and Article 470 paragraph 1 CC says the reserve protects those who leave descendants, a spouse or a registered partner. Parents are no longer reserved heirs.

That is the result of the revised succession law, adopted by the Federal Act of 18 December 2020 and in force since 1 January 2023, after the Federal Council fixed the date on 19 May 2021. The Federal Office of Justice presents the reform as a way to let people dispose freely of a larger share of their assets. The reserve has not disappeared; it has become smaller and narrower.

Other legal families work differently:

• Civil-law systems generally combine a freely disposable portion with a protected one, though who is protected and how much differs sharply from one country to the next.
• Common-law systems historically favour testamentary freedom, with family provision claims that a court may grant based on need rather than a fixed share.
• Mixed or Islamic-law systems may apply fixed fractions on religious or customary grounds.

A trust created in one family of systems can therefore end up being assessed under the rules of another. For the wider contrast between the two traditions, see the comparison of common-law seats versus civil-law seats.

Why a trust does not remove reserved claims automatically

A common assumption is that moving assets into a trust during life takes them out of the estate, so there is nothing left for heirs to claim. Civil-law courts do not usually see it that way. Their concern is substance: if a person gave away property shortly before death in a way that cuts into a protected share, the heirs can ask for the gift to be reduced, whatever label the transfer carries.

Switzerland shows the logic clearly. Trusts fall under Article 149c of the Private International Law Act (PILA), which refers to the Hague Convention for the applicable law. The Convention itself, however, holds back. Article 15 states that it does not stand in the way of the mandatory rules of the forum on a list of subjects: the protection of minors and incapable persons, the effects of marriage, succession rights, the transfer of title, the protection of creditors and the protection of third parties acting in good faith. Succession rights are on that list in plain words.

In other words, recognising a trust and letting it override reserved shares are two separate questions. A Swiss court can accept that a trust exists, apply the law the settlor chose to its internal workings, and still apply Swiss mandatory succession rules to the transfer that funded it. The guide to the Hague Trusts Convention goes through the Convention's structure in more detail.

The Convention's definition in Article 2 also matters here. A trust is a legal relationship, created during life or on death, in which assets are placed under the control of a trustee for a beneficiary or a specified purpose. The assets form a separate fund, title is in the trustee's name, and the trustee must manage and account. Powers kept by the settlor, or the trustee also being a beneficiary, do not by themselves defeat the trust. That wide definition is why a trust built for asset-protection reasons can be recognised and still be attacked on succession grounds.

Firewall statutes: the common-law answer

Several trust seats responded to the problem by legislating. A firewall provision directs the local court to decide questions about a trust under the law of that seat, and to disregard foreign rules that would otherwise invalidate or reduce the trust. Typical features include:

• a statement that a trust is not void or voidable because it defeats a right of forced heirship under a foreign system;
• a rule that the personal relationship between settlor and heirs, and the validity of transfers, are not grounds for challenging the trust locally;
• a refusal to enforce foreign judgments that rest on such claims, at least as regards trust assets located in the seat;
• carve-outs, usually for fraudulent transfers and for cases where the settlor was insolvent when the assets moved.

The concept is explained in the glossary entry on firewall legislation, and a broader survey of protective statutes is in the comparison of asset-protection statutes.

What a firewall statute does is bind its own courts. It cannot bind a court in the heirs' country. That is the central limit, and the next section turns it into a seat-by-seat view.

Seats compared on the points that decide a claim

The table below summarises the typical position. It is deliberately qualitative: statutes change, details differ between seats within each group, and an individual analysis is always needed.

A reading of the table: none of the columns offers a clean answer. The offshore firewall seats offer the strongest local statutory position against reserved shares, but their protection works only where the assets or the trustee can be reached solely through their own courts. Switzerland offers stability, regulated trustees and bank custody, but not a statute that switches off Swiss mandatory rules. US states are rarely the source of the problem because their own law does not impose reserved shares; they matter mainly when a US-linked settlor is involved.

Where Switzerland actually sits

Switzerland is a hybrid in this debate. It is a civil-law country with reserved shares, yet it recognises foreign-law trusts and hosts regulated trustees who administer them. It has no trust statute of its own: a parliamentary motion (18.3383, "Introduction of the trust into the Swiss legal order"), filed on 26 April 2018, asked the Federal Council to create the legal basis for a Swiss-law trust, and its status in the parliamentary database is "written off" as of 27 February 2024. A Swiss trust law therefore remains a topic for the future.

Two consequences follow for forced heirship.

First, a trust administered in Switzerland under a foreign governing law does not carry a firewall. The foreign law may contain one, and the trust deed may choose it, but a Swiss court deciding on a Swiss-resident settlor's estate will look at Article 15 of the Convention and at Swiss mandatory succession rules. For a settlor domiciled in Switzerland at death, the practical risk is a reduction claim by protected heirs against the lifetime transfer.

Second, the answer changes with the settlor's links. If the settlor was never a Swiss resident, never held Swiss real estate and the heirs have no Swiss link, the Swiss reserved shares may simply not be engaged. The question then becomes what the settlor's own country, and the country where the heirs live, would do. The international side of Swiss succession law has also been reformed: the amendment of the PILA on international successions took effect on 1 January 2025, following the Federal Council's decision of 26 June 2024. Anyone with a cross-border estate should have the interaction between the new rules and a trust reviewed individually.

For the strengths and limits of Switzerland as a place to administer a trust, read Switzerland as a trust seat. For a head-to-head view with a leading firewall seat, see Switzerland versus Jersey.

Four things that decide whether a heir's claim succeeds

Looking only at the seat's statute is a mistake. In practice, four factors usually decide the outcome.

The law governing the succession

The settlor's last habitual residence or nationality, depending on the conflict rules of the court hearing the case, determines which reserved-share regime is even considered. A trust seat in a firewall jurisdiction does not change that. The distinction between governing law and seat is covered in governing law versus seat of administration.

Where the assets are

Real estate and bank accounts are usually reachable by the courts of the place where they are located, whatever the trust deed says. Trust assets in a firewall seat are harder for a foreign claimant to reach than a house in the heirs' home country. The rules of situs are set out in the glossary entry on situs of trust assets.

Whether the trustee and the assets can be reached at all

A foreign judgment reducing a transfer is only useful if it can be enforced. Where the trustee is regulated in the seat, holds assets there and has no presence in the heirs' country, enforcement often depends on the seat's own rules on foreign judgments. Where the trustee or the custodian has a presence in the heirs' country, the picture changes.

The settlor's own conduct

Courts look hard at timing and intention. A transfer made long before death to a structure that the family genuinely uses is treated differently from a last-minute transfer made to defeat a known claim. A settlor who also keeps broad control, or who remains the practical beneficiary, may find that the arrangement is treated as part of the estate. Reserved powers are compatible with a trust under the Convention, but the more control kept, the weaker the argument that the assets left the estate.

An illustration

Take a fictional example: a settlor who lived for many years in Geneva, with children from a first marriage and a second spouse. The settlor transfers a portfolio to a trust governed by the law of a firewall seat, administered there, with the second spouse and the younger children as discretionary beneficiaries.

On death, the older children claim their reserved share under Swiss law. They bring an action in Switzerland. The Swiss court treats the settlor's last residence as decisive and, under the Convention's reservation for succession rights, applies Swiss mandatory rules to the lifetime transfer. A judgment reducing the transfer may follow. Whether it bears fruit depends on where the portfolio is, who holds it and whether the firewall seat will enforce the judgment. If the portfolio is held in the firewall seat by a local trustee, the claimants face a second contest there. If part of it sits in a Swiss bank account, the claim reaches that part directly.

The same facts with a settlor who had always lived in a country without reserved shares would look very different. This is why families with children in different places often ask for an individual review; the page on blended-family and vulnerable-beneficiary trusts looks at those personal factors.

Questions to settle before choosing a seat

• Which country's law will govern the settlor's succession at death?
• Do any heirs live in a country with reserved shares or a family provision regime?
• Where are the main assets located, and who holds them?
• Does the seat have firewall provisions, and what are their stated exceptions?
• Would a judgment from the heirs' country be recognised in the seat?
• How much control does the settlor keep, and could it undermine the separation from the estate?
• What happens if the settlor moves country later? See trust law when the settlor relocates.