Iowa Code § 261A.47: Money received by authority.

All money received by the authority, whether as proceeds from the sale of obligations, from revenue, or otherwise, shall be deemed to be trust funds to be held and applied solely as provided in this subchapter, but prior to the time when needed for use may be invested to the extent and in the manner provided by the authority. The funds shall be deposited, held, and secured as determined by the authority, except to the extent provided otherwise in the resolution authorizing the issuance of the related obligations or in the trust agreement securing the obligations. The resolution authorizing the issuance of the obligations or the trust agreement securing the obligations shall provide that an officer, bank or trust company to which the money is entrusted shall act as trustee of the money and shall hold and apply the money for the purposes of this subchapter, subject to the provisions of this subchapter and of the authorizing resolution or trust agreement.