A unit holder can be either one or more people, a company, a trustee of a family trust or any other trust or a combination of them all.
Much like shares held in a company, units held by a unit holder carry certain rights (the right to receive distributions of income and capital and the right to vote at unit holder meetings).
Some decisions that must be made by the trustee with regards to the operation of the trust must have the consent of the unit holders before they can proceed. These can include changes to the ownership of the trust, changes to the trust deed and changing the trustee.
Minors under law cannot hold units in a unit trust.