The reporting requirements have evolved from Anti-Money Laundering laws over the last few decades. Basically, it helps the government find and prosecute individuals or organizations that are committing crimes and/or trying to make dirty money clean.
What is reportable?
If it is a cash transaction (defined below) that is:
What is considered CASH?
What is NOT considered CASH
You buy $12,800 worth of gold coins and silver bars and pay using $8000 in US currency and a cashier’s check of $4,800.
Yes. Since the cashiers check is less than $10,000 it is considered cash. As such, the total cash you have given is $12,800.
You buy $12,800 worth of gold coins and silver bars and pay using $1,800 in US currency and a cashier’s check of $11,000.
No. Since the cashier’s check is more than $10,000 it is not considered cash. As such your total cash payment is only $1,800.
You buy gold bars for $33,000 and pay using a personal check for $25,000 and $8,000 in US currency.
No. Any payment, regardless of the amount drawn from your personal account is NOT considered cash. The cash payment is less than $10,000
You buy gold Canadian Maple Leaf coins for $12,000 and make a payment in US currency for $8,000 on April 2. You make another US currency payment on April 15 of $4,000 and receive your gold coins.
Yes. These are considered installment payments and are combined to total more than $10,000.
A more detailed explanation and definitions can be found on the IRS’s website here