The amount of cash or money that an ATM holds will depend on the size of the ATM.
The ATM machines at Banks hold around $50,000.00 to $100,000.00 in cash which is a lot of money but goes quickly if enough bank account holders withdraw cash enough and it can be gone within 1 or 2 days.
ATM machines are kept as full as possible with cash to avoid running out but the smaller ATM machines may only hold as much as $1,000.00 to $15,000.00
Larger ATM machines are the ones that hold the most cash.