Each person engaged in a trade or business who, in the course of that trade or business, receives more than $10,000 in cash in one transaction or in two or more related transactions, must file Form 8300. Transactions occurring between the payor and the recipient business within 24 hours are considered related transactions. If the transactions occur over a longer period, they are still considered related if the recipient business knows, or has reason to know, that each transaction is one of a series of connected transactions