A banker's mark (or bankers' mark) is a symbol or letter stamped or scratched into many republican and early imperial

Roman coin Roman currency for most of Roman history consisted of gold, silver, bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, ...

s, whose purpose is unclear. The marks are found on either the obverse or reverse of a coin. 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. There is also debate as to why these marks stopped appearing after very early imperial Roman coinage.

References

{{Reflist Roman archaeology Numismatic terminology