Ariz. Rev. Stat. § 15-1688
No monies derived from the sale of bonds issued under the provisions of this article or pledged or assigned to or in trust for the benefit of the holder or holders of the bonds shall be required to be paid into the state treasury but shall be invested in obligations issued by or guaranteed by the United States or any of the senior debt of its agencies, sponsored agencies, corporations, sponsored corporations or instrumentalities, or shall be deposited by the treasurer or other fiscal officer of the board in such bank or banks or trust company or trust companies as may be designated by the board, and all deposits of such monies shall, if required by the board, be secured by obligations of the United States of a market value equal at all times to the amount of such monies on deposit. Such monies shall be disbursed as may be directed by the board and in accordance with the terms of any agreements with the holder or holders of any bonds. This section shall not be construed as limiting the power of the board to agree in connection with the issuance of any of its bonds as to the custody and disposition of the monies received from the sale of such bonds or from the income and revenues pledged or assigned to or in trust for the benefit of the holder or holders of the bonds.
A.R.S. § 15-1688