Interest Paid on Security Deposits?

[Shafi Noss]

I'm studying for my license and ran into this paragraph on the study materials

"The landlord must return security deposits within 45 days of lease
termination; on security deposits of $50 or more, the landlord must also
pay the tenant simple interest on that deposit. The specific interest
rate varies, based on Maryland law."

Is this true? I've never heard about it before. Does anyone know how to find the appropriate interest rate is for a particular lease?