Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

What happens if one brings more than 10,000 USD with them into the US?
Once you declare the amount, the CBP officials will ask you the source and purpose of funds. You must be able to demonstrate that the source of funds is legitimate and not the proceeds of crime and it is not for the purposes of financing terrorism. Once they have determined that the source and purpose is legitimate, they will take you to a private room where two officers will count and validate the amount (as it is a large amount); and then return the currency to you. For nominal amounts they count it at the CBP officer's inspection desk. Once they have done that, you are free to go on your way. The rule (for the US) is any currency or monetary instrument that is above the equivalent of 10,000 USD. So this will also apply if you are carrying a combination of GBP, EUR and USD that totals to more than $10,000.