This article examines whether the interest of a discretionary trust beneficiary can be valued under standard principles. It is argued that these interests, like any other income producing right, can be valued with the hypothetical market transaction test based on the estimated future income. This argument requires detailed examination of the assumptions about the participants in the hypothetical market transaction. In relation to the rights that often accompany discretionary interests, such as rights to remove trustees, another assumption is important: that the holder of an interest will use it self-interestedly. This raises the possibility that rights to remove trustees are fiduciary and self interest is prohibited. Consideration of the value of discretionary interests is important to the argument about whether these interests can ever be property.