The Maryland Real Property Code stipulates that the security deposit for a rental premises cannot exceed 2 months' rent. Landlords must pay 3% interest per year on deposits of $50 or more. Interest is simple interest (not compounded), and accrues every 6 months of the term of the lease or tenancy.
The landlord must issue a receipt for the security deposit. The security deposit must be kept in a separate bank account until the end of the tenancy, and returned to the tenant (plus accrued interest, minus any charges for damages or late rent) within 45 days after the tenant has vacated the premises.