Mont. Code Ann. § 72-38-121
Resulting trust upon full performance of trust
72-38-121 . Resulting trust upon full performance of trust. When the owner of property gratuitously transfers it subject to a trust that is properly declared and that is fully performed without exhausting the trust estate, the trustee holds the surplus as a resulting trust for the transferor or the transferor's estate unless the transferor manifested in the trust instrument an intention that no resulting trust of the surplus should arise.