From January 1, 2019 through December 31, 2019, the security deposit interest rate is set at 0.01% (unchanged since 2015).
For example, if a landlord collects a security deposit for $1,000.00, the landlord will owe $0.10 in interest to the tenant every 12 months.
The Security Deposit Interest Act (765 ILCS 715) requires that the lessor of residential real property, consisting of 25 or more units, pay interest to the lessee on any security deposit held for six months or more. Interest must be paid to the lessee in cash or in the form of credit towards rent within 30 days after the end of each 12 month rental period at a rate equal to the interest paid by the largest commercial bank in Illinois on minimum deposit passbook savings accounts as of December 31 of the calendar year preceding the inception of the rental agreement. This Act does not apply to deposits made with respect to public housing, nor to a lessee who is in default under the terms of the lease.
For more information, please see the Security Deposit Interest Act.
As of December 31, 2018, The Northern Trust Company, Chicago was the largest commercial bank with its main banking premises in Illinois.