Ind. Code § 5-1.5-9-6
A financial institution may give to the bank a good and sufficient undertaking with such sureties as are approved by the bank to the effect that the financial institution shall faithfully keep and pay over to the order of or upon the warrant of the bank or its authorized agent all those funds deposited with it by the bank and agreed interest under or by reason of this article, at such times or upon such demands as may be agreed with the bank or in lieu of these sureties, deposit with the bank or its authorized agent or a trustee or for the holders of bonds, as collateral, those securities as the board may approve. The deposits of the bank may be evidenced by an agreement in the form and upon the terms and conditions that may be agreed upon by the bank and the financial institution.
IC 5-1.5-9-6