A banker’s mark is a small symbol, letter, or punch mark stamped or scratched into a coin by a banker or merchant to indicate that they considered the coin genuine and of acceptable weight. The marks are found on either the obverse or reverse.
Their exact purpose is not entirely settled. Numismatists have proposed several explanations: testing silver purity, confirming the coin was not a plated forgery, accounting, or administrative identification. Research suggests that no single explanation covers all cases – a combination of purposes is more likely.
Similar private marks applied to coins circulating in China and Japan are known by a different term: chop marks.
For collectors, banker’s marks are original to a coin’s history and are not considered damage in the modern sense. Their presence, however, typically reduces a coin’s grade and market value compared with an unmarked example of the same type.