A trustee who invests badly, or fails to invest at all, can find the trust fund diminished and a breach of trust claim following close behind. This chapter begins with the powers themselves — the general power of investment under the Trustee Act 2000 and the separate power to acquire land — before turning to the duties that shape their exercise: the standard investment criteria of suitability and diversification, and the obligations to take advice and keep investments under review. It then examines the statutory duty of care, the higher standard expected of professional trustees, the requirement of even-handedness between life tenant and remainderman, and the limited room for ethical investment policies in private and charitable trusts. Finally, it covers the rules on delegating investment management to agents, and the remedies, defences, exemption clauses and limitation periods that determine what happens when investment duties are breached.