We are not aware of any laws that would require your institution to take any actions as to the matured certificates of deposit (CDs). If the customers choose not to renew the CDs, and the original agreements did not provide for automatic renewals, then you have no obligation to renew or pay interest on the deposits.
Note that Regulation D may require your institution to reclassify the accounts as demand deposits (but only for purposes of computing your reserve requirements under 12 CFR 204.4). Any time deposit that has matured without being renewed is included in the definition of “demand deposit.” 12 CFR 204.2(b)(1)(vii). The regulation requires banks to reclassify any “time deposits upon which the contractually required notice of withdrawal as given and the notice period has expired and which have not been renewed (either by action of the depositor or automatically under the terms of the deposit agreement).
Also, note that it may be some time before the CDs should be reported as unclaimed property to the State Treasurer. Normally, if CD accounts remain inactive for five years from the date of maturity, with no communications from an owner, then your institution would have to report them as unclaimed property. 765 ILCS 1025/2(c) [Repealed effective 1/1/18]. However, a special rule applies to property held in an individual retirement account (IRA), and such accounts are “not presumed abandoned earlier than 5 years after the owner attains the age at which distributions from the account become mandatory under law.” 765 ILCS 1025/2(e) [Repealed effective 1/1/18]. (Under current IRS rules, mandatory IRA distributions begin at age 70½. IRS Retirement Plans FAQs, Question 1.)