Any amount of money you deposit into a USA bank account is eventually reported to the IRS which is what the bank has to do by law.
Banks will report every transaction you make at a bank through your account such as deposits and withdraws of money at the end of the year.
However if you deposit $10,000.00 or more whether in cash or by check or direct deposit in one day then the bank will report that deposit to the IRS right away since they have too by law.
So if you deposit $10,000.00 or more in a bank account then you might be audited by the IRS and capture the IRS attention.