Banker's mark

A banker's mark (or bankers' mark) is a symbol or letter stamped or scratched into many republican and early imperial Roman coins, whose purpose is unclear.^[1][2][3][4]

Denarius of 83 BCE, depicting Venus, with a banker's mark next to the tip of her nose

The marks are found on either the obverse or reverse of a coin.^[1]

Historians and numismatists have speculated that the marks may have been used to assess the purity of a coin's silver, demonstrate that it was not a plated forgery, for accounting or auditing purposes, or to denote that the coin did or did not have the specified weight.^[1][5]

There is also debate as to why these marks stopped appearing after very early imperial Roman coinage.^[1]