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Author and Publication
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Citation
Mental Capacity Act 2005, c. 9. Available at: https://www.legislation.gov.uk/ukpga/2005/9/contents
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Copyright © 2026 Nellie Supports Ltd. All rights reserved.
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Testamentary assessments for clients with complex financial structures
Testamentary capacity requires understanding the extent of the estate in broad terms, not accountancy-grade precision, and that principle is what makes assessment workable for clients with trusts, business interests, cross-border assets and layered structures. The assessment focuses on whether the person broadly grasps what they own, what is actually theirs to leave, who might expect to benefit and the effect of the will they propose. Complexity raises the preparation the assessment needs, not the legal bar the person must meet. This guide explains how assessments handle complex structures and what advisers should prepare in advance.
Complex assets change the assessment question
A person does not need to understand every technical detail of a trust deed, business account or foreign property arrangement. However, the more complex the estate, the more carefully the assessor must identify what the person needs to understand in broad terms to make a valid will decision.
Apply the right legal test
Testamentary capacity is usually considered through the Banks v Goodfellow framework. For complex estates, the assessor should look at whether the person understands the nature and effect of making a will, the broad extent of their property, the claims of potential beneficiaries and whether any disorder of the mind affects the decision. The complexity should be translated into relevant, accessible information.
Trusts create different questions from businesses
Trust complexity may involve beneficial interests, trustees, life interests, discretionary beneficiaries, letters of wishes and whether assets are actually part of the person’s estate. Business complexity may involve shares, partnerships, directorships, trading risk, succession planning, dependent employees and family control. The assessment should not treat these as the same problem.
Cross-border assets need legal context
Where overseas assets are involved, the assessor should not provide foreign succession advice. However, the report may need to record that the person has a broad understanding that property or interests exist outside England and Wales, that different rules may apply, and that professional legal advice has been taken or is needed.
The solicitor’s summary is crucial
In complex financial cases, the assessor usually needs a concise solicitor-prepared summary rather than a large unsorted bundle. The summary should explain the proposed will, previous wills, asset categories, potential beneficiaries, excluded people, trusts, business interests, overseas assets and any known dispute or undue influence concern.
Separate legal complexity from cognitive complexity
Some estate structures are legally complex but can still be explained in a way the person understands. The report should distinguish complexity caused by legal drafting from difficulty caused by impairment, confusion, memory problems or inability to weigh competing claims.
Watch for control of information
Complex financial structures can create dependency on advisers, relatives or business partners. The assessor should consider whether the person has access to independent information, whether someone else controls documents, and whether the person can explain the decision in their own words.
What a strong report should cover
A strong report should identify each source of complexity, explain what was simplified for the person, record the person’s own explanation, consider potential beneficiaries and exclusions, and state clearly whether missing information limits the opinion.
Key takeaway
Trusts, businesses and cross-border assets should not be grouped together as generic financial complexity. Each creates different relevant information, different risks and different evidence needs. A good testamentary assessment makes those differences clear.
Frequently asked questions
Can someone have testamentary capacity with a complex estate?
Yes. Complexity does not automatically prevent capacity. The question is whether the person can understand and weigh the relevant information at the level needed for their will decision, with appropriate support and explanation.
Does the person need to know the exact value of every asset?
Usually, they need a broad understanding of the extent and nature of their estate rather than precise valuations for every asset. In complex cases, approximate values, asset categories and the practical effect of the will may be more important than exact figures.
How do trusts affect testamentary capacity?
Trusts may affect what assets are actually available to leave by will and what expectations beneficiaries may have. The assessment should focus on the person’s broad understanding of their interest, the people affected and the consequences of the proposed will.
Related mental capacity assessment pages
These internal links help readers move from this guide to the most relevant Nellie Supports service page, assessment option or legal framework page.
Complex estate needing capacity evidence?
Nellie Supports completes testamentary capacity assessments across England and Wales, prospective, contemporaneous and retrospective, through a permanent employed team with every report peer reviewed before delivery. Call 0333 987 5118 or visit the testamentary capacity assessment service page.