Trustees Lecture 1 Judith Puech Track/Slide 28 An important aspect of safeguarding the trust assets is the duty to invest. Trustees have a duty to invest, i.e. they must invest but a power over what they can invest in. What trustees can and can't invest in is governed firstly by statutory default provisions, previously the Trustee Investment Act 1961, now the Trustee Act 2000, or by an express power in the trust document.