R.I. Gen. Laws § 35-10.1-8: Insurance.

At its option, a depository institution may elect to purchase insurance for one hundred percent (100%) of any public deposit not covered by federal deposit insurance or secured pursuant to this chapter; provided, that this insurance is provided by an insurer rated “AAA” by standard & poor’s corporation, moody’s investors service, or both. This insurance may be provided in lieu of, but shall not be required in addition to, collateral otherwise required pursuant to this chapter.