(1)The credit union may deposit, maintain, pledge and assign for the benefit of the public officer in the manner provided in this chapter, securities approved by the public officer, the market value of which is not less than one hundred percent of the total deposits of public funds placed by that public officer in the credit union, less the amount of deposits that are federally insured. The securities shall consist of any of the following:
(a) Direct obligations of, or obligations that are insured or fully guaranteed as to principal and interest by, the United States of America or an agency or instrumentality of the United States of America.(b) Public bonds or obligations of this state or a political subdivision of this state.(c) Public bonds or obligations of another state or a political subdivision of another state whose bonds are rated within the two highest classifications of prime as established by at least one of the standard rating services approved by the superintendent of banking pursuant to chapter 17A.(d) To the extent of the guarantee, loans, obligations, or nontransferable letters of credit upon which the payment of principal and interest is fully secured or guaranteed by the United States of America or an agency or instrumentality of the United States of America, a corporate central credit union organized under section 533.213, or a corporate credit union whose activities are subject to regulation by the national credit union administration, and the rating of any one of such credit unions remains within the two highest classifications of prime established by at least one of the standard rating services approved by the superintendent of banking by rule pursuant to chapter 17A. The treasurer of state shall adopt rules pursuant to chapter 17A to implement this section.(e) First lien mortgages which are valued according to practices acceptable to the treasurer of state.(f) Investments in an open-end management investment company registered with the federal securities and exchange commission under the federal Investment Company Act of 1940, 15 U.S.C. § 80a-1 et seq., which is operated in accordance with 17 C.F.R. § 270.2a-7.