(9) Certificates of deposit or share certificates issued to the depository institution pledging them as security. The public agency may require security in the amount of 125% of the value of the public agency deposit. Such certificate of deposit or share certificate shall:
(i) be fully insured by the Federal Deposit Insurance Corporation, the Federal Savings and Loan Insurance Corporation, or the National Credit Union Share Insurance Fund or issued by a depository institution which is rated within the 3 highest classifications established by at least one of the 2 standard rating services; (ii) be issued by a financial institution having assets of $15,000,000 or more; and (iii) be issued by either a savings and loan association having a capital to asset ratio of at least 2%, by a bank having a capital to asset ratio of at least 6% or by a credit union having a capital to asset ratio of at least 4%. The depository institution shall effect the assignment of the certificate of deposit or share certificate to the public agency and shall agree that, in the event the issuer of the certificate fails to maintain the capital to asset ratio required by this Section, such certificate of deposit or share certificate shall be replaced by additional suitable security.