A letter of testamentary—also known as letters testamentary—is a written order from a probate court approving the appointment of an executor under a will and authorizing the executor to administer the will and the decedent’s estate—including collecting amounts due to the estate, paying any outstanding debts of the estate, and distributing the assets of the estate in accordance with the provisions of the will.

Banks, brokerages, and mortgage and title companies rely on the court-ordered authority of the executor—as demonstrated by a letter of testamentary—when transferring ownership and control of assets in the testator’s estate.

When a deceased person (decedent) dies without a will (intestate) or the decedent’s will is found to be invalid by the probate court, the court may appoint an administrator to manage the estate, assets, and liabilities of the decedent. The administrator must be qualified or approved by the court and in some instances may be required to post a bond to secure the assets of the estate.

Upon appointment of an administrator by the probate court the court may issue letters of administration that authorize the administrator to administer the decedent’s estate by collecting amounts due to the estate, paying any outstanding debts of the estate, and distributing the assets of the estate in accordance with the state’s intestate succession laws.

Laws and procedures vary from state to state but an administrator—and the administrator’s administration of the estate—may be supervised or unsupervised by the probate court and may be with or without a bond required from the administrator.

In Michigan, a letter of testamentary is a legal document issued by a probate court that grants an executor the authority to administer a deceased person's estate as specified in their will. This document is necessary for the executor to manage estate affairs, such as collecting debts owed to the estate, paying outstanding debts, and distributing assets to beneficiaries according to the will. If a person dies intestate (without a valid will) or the will is deemed invalid, the probate court appoints an administrator to manage the estate. The court may require the administrator to post a bond as a security measure for the estate's assets. The administrator receives letters of administration, which empower them to handle the estate in line with Michigan's intestate succession laws. The extent of court supervision over an administrator's actions and whether a bond is required can vary. Michigan law outlines specific procedures for both testate (with a will) and intestate (without a will) estate administration, and it is important for executors and administrators to follow these legal guidelines to ensure proper management of the decedent's estate.