The term trustee de son tort refers to an individual that has been placed in the role of trustee by operation of the law. Trustees de son tort are not selected by the settlor, rather they are chosen due to their interference with the operation of the trust.
Derived from the French language, de son tort translates into the English as "of his wrong." A trustee de son tort arises as a result of a tort, crime, or even a breach of duty. As is the case with a trustee ex maleficio, a trustee de son tort is created through the operation of law and is therefore associated with the broader category of constructive trusts. These are court imposed, legal remedies to correct a harm.
While a trustee ex maleficio is created to remedy the unjust enrichment of one party, a trustee de son tort is created as a result of any type of wrongdoing. For example, if a trustee does not fulfil their fiduciary responsibilities to a beneficiary, a court of law may designate a trustee de son tort and direct that party to carry out the duties of the trustee.