Trustees have certain duties (some of which are fiduciary). These include the duty to carry out the express terms of the trust instrument, the duty to defend the trust, the duty to prudently invest trust assets, the duty of impartiality among the beneficiaries, the duty to account for their actions and to keep the beneficiaries informed about the trust, the duty of loyalty, the duty not to delegate, the duty not to profit, the duty not to be in a conflict of interest position and the duty to administer the trust in the best interest of the beneficiaries. These duties may be expanded or narrowed by the terms of the instrument creating the trust, but in most instances cannot be eliminated completely.
A trustee carries the fiduciary responsibility and liability to use the trust assets according to the provisions of the trust instrument (and often regardless of their own or the beneficiaries' wishes). The trustee may find himself liable to claimants, prospective beneficiaries, or third parties. In the event that a trustee incurs a liability (for example, in litigation, or for taxes, or under the terms of a lease) in excess of the trust property they hold, they may find themselves personally liable for the excess.
Trustees are generally held to a "prudent person" standard in regard to meeting their fiduciary responsibilities, though investment, legal, and other professionals can be held to a higher standard commensurate with their higher expertise. Trustees can be paid for their time and trouble in performing their duties only if the trust specifically provides for payment. It is common for lawyer's to draft will trusts so as to permit such payment, and to take office accordingly: this may be an unnecessary expense for small estates.
In the case of UK charities, a trustee is an unpaid volunteer who undertakes fiduciary responsibilities on behalf of the charity, subject to the provisions of Charity Law, a branch of trust law, and the Charities Act 1993. For charity trustees, the Charity Commission of England and Wales, Office of the Scottish Charity Regulator of Scotland and Voluntary Activity Unit of Northern Ireland often has concurrent jurisdiction with the Courts. Many UK charities are also limited liability companies registered with Companies House, in this case the trustees are also Directors of the company and their liability is limited. This is the preferred model if the charity owns property or employs people.
Trustee is also a term used for a prison inmate who has special work-related privileges, usually as a result of good behavior.