Codicil
Last updated 17 July 2026
A codicil is a legal supplement that amends specific provisions of an existing will without rewriting the whole document. Rather than revoking the will and starting again, the testator (the person who made the will) executes a short instrument that changes, adds, or removes particular terms while leaving the rest in force. Codicils are a feature of common law systems and must be executed with the same formalities as the will itself, typically signing before witnesses, to be valid.
Typical uses are targeted: replacing a named executor who has died or become unsuitable, updating a specific gift, or exercising a testamentary power of appointment granted under a trust.
Why it matters for family offices
For families with substantial estates, the will is rarely a static document. Executors age, assets are sold, family circumstances shift, and trusts created by earlier generations may require appointments to be exercised by will. A codicil offers a fast, low-cost way to keep the document current between full reviews. It also carries risks worth understanding. Multiple codicils layered over decades can create ambiguity or outright conflict between provisions, and a misplaced codicil can change an estate's outcome without anyone realising until probate. For that reason many advisers recommend a fresh will once changes accumulate, reserving codicils for genuinely simple amendments.
How it shows up in practice
Consider a matriarch whose will names her brother as executor. When he retires abroad, she executes a one-page codicil substituting her daughter, signed and witnessed with full formality, and the rest of the will stands untouched. In a family office context, the practical work is record-keeping: knowing which documents exist, where the originals are held, and which codicils attach to which will. Offices that maintain a document register for each family member, covering wills, codicils, powers of attorney, and healthcare directives, spare executors a scramble at the worst possible time.
Related terms
Will
A legal document directing how a person's assets are distributed at death and, where relevant, who will care for minor children. For UHNW individuals, the will works alongside trusts and entity structures, often functioning as a backstop that pours remaining assets into trusts. Dying without a valid will leaves distribution to statutory default rules, an outcome no wealthy family intends.
Executor
The person or institution appointed in a will to administer the deceased's estate: gathering assets, paying debts and taxes, and distributing what remains according to the will. For complex estates, executors work closely with the family office, which often holds the records that make administration possible. Choosing capable, impartial executors is a key estate planning decision.
Testamentary Power of Appointment
A power of appointment that can only be exercised at the holder's death, typically through their will or a codicil to it. It lets each generation fine-tune how trust assets pass to the next, without giving anyone the ability to redirect wealth during life. Testamentary powers are a common tool for keeping dynasty structures adaptable across decades.
Power of Appointment
A right granted under a trust or will allowing its holder to direct where certain trust property goes, within limits set by the document. Powers of appointment build flexibility into long-lived structures, letting future generations redirect wealth as circumstances change. Some trusts appoint a power-of-appointment committee to exercise this right collectively.
Estate Planning
The legal and financial arrangement of a person's assets to ensure they are transferred according to their wishes, with minimal tax friction and family conflict. Tools include wills, trusts, holding structures, and lifetime gifting strategies. For UHNW families, estate planning is a continuous discipline that must keep pace with changing laws, asset values, and family circumstances.
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