A settlor may leave property absolutely to a minor. The
property cannot be transferred until the minor reaches the age of
majority. This is because a minor is not able to give a valid
receipt. Until then the property is held in a trust for the
minor.
When the minor comes of age, he is no longer legally incapacitated. He can give a valid receipt, and manage his own affairs. The legal term for this is sui juris. He is entitled to the trust property. This includes any investments the trustees made out of accumulated income.
He can require the trustees to relinquish their trusteeship. There is no point in their continuing the trust any longer.