Completely and incompletely constituted trusts
 
In all cases the trust must be completely constituted.  A trust is completely constituted when the trust property has been vested in trustees for the benefit of the beneficiaries.  Where there is merely a contract or covenant to create a trust, the trust is said to be incompletely constituted.

A completely constituted trust may be enforced by any beneficiary, including a volunteer; an incompletely constituted trust can only be enforced by a beneficiary who has given value. Thus a trust is incompletely constituted where there is merely a covenant by a settlor to settle property which he expects to acquire. If the settlor does not settle the property when he eventually acquires it, although he will be liable in damages to the intended beneficiaries, if they were parties to the covenant, and the covenant was under seal, those beneficiaries,if volunteers, cannot enforce their expected beneficial interest in the property to be settled.