Under New York state law, specifically Section 7-103 of the General Obligations Law, the security deposit you provide when renting a property remains your exclusive property and cannot be mixed with the landlord's personal assets.
If you reside in a building with 6 or more residential units, the regulations strictly enforce the obligation to deposit this money into a US bank account that yields interest periodically.
How much can the landlord keep?
The law permits the landlord to retain an administrative fee equal to 1% annually of the total deposit amount, deducted only from the generated interest. If the account yields less than that 1%, they can only retain the actual interest generated.
The 'Commingling' rule
If your landlord mixes your money with their personal or commercial accounts, they commit a serious violation. Under the law, if they commingle funds, they forfeit the right to retain any portion of your security deposit, even if you left damages in the apartment.