Per the IRS website: Transactions that require Form 8300 include, but are not limited to: escrow arrangement contributions, per-existing debt payments, negotiable instrument purchases, reimbursement of expenses, making or repaying a loan, sales of goods or services, sale of real property, sale of intangible property, rental of real or personal property, exchange of cash for other cash, custodial trust contributions.

"Who Must File: A "person" who must file From 8300 includes an individual, company, corporation, partnership, association, trust, or estate. You must file Form 8300 with the IRS if any part of the transaction occurs within any of the 50 states, the District of Columbia or a U.S. possession or territory. . ."

You don't have to file it on the spot; it needs to be filed by the 15th day after the cash deposit is made. And the bank will make separate reports of large deposits to the IRS.