Utah Code § 75B-1-203: Income permitted to accumulate.

The income arising from or earned by the property held in a retirement trust is permitted to accumulate, in accordance with the terms of the trust:

(1) for the time period permitted by the instrument creating the trust; or

(2) if the instrument creating the trust does not specify a time period, for the time period that is necessary for a trustee of the trust to accomplish the purposes for which the trust was created.