If you try to withdraw $10,000 worth of paper, yes, the bank will ask you questions, because they don't keep every dollar worth of deposits in the bank branch in paper notes. They don't even know which branch you're going to want to withdraw that money from on a given day, so it's hard to prepare for. But you can invest $10,000 in bitcoin/gold/stocks, or buy a large appliance or vehicle, relax at a resort, shop at a mall, etc in one day and no one blinks twice. You can also send it to another institution here or another country and no one will stop you, though you might have to fill out a wire transfer. So I guess the more pertinent question is… Why does anyone want $10,000 worth of physical fiat paper in their hand? To stuff under a mattress?(𝐓𝐗𝐌𝐂)