Wildcat banking was the issuance of paper currency in the United States by poorly capitalized state-chartered banks. These wildcat banks existed alongside more stable state banks during the Free Banking Era from 1836 to 1865, when the country had no national banking system. States granted banking charters readily and applied regulations ineffectively, if at all. Bank closures and outright scams regularly occurred, leaving people with worthless money.

Operating in remote locations with limited or absent financial infrastructure, wildcat banks supplied a medium of exchange in the form of bearer notes that they issued on their own credit. These notes were formally redeemable in specie (i.e. gold or silver coins) but typically collateralized by other assets such as government bonds or real estate notes, or occasionally by nothing at all. Hence they carried a risk that the bank could not redeem them on demand.