Imitative coinage is understood to be any currency issued outside of the official known coin series. This currency could have been issued by individuals or state agents, and its main function was not profit, but rather it responded to currency shortages and acted as a currency of necessity. It must be distinguished from the currency itself, which had a lucrative intent on the part of the issuers. Coin imitation was a phenomenon that occurred during various chronological periods throughout the Roman Imperial era, essentially linked to historical events that caused a monetary shortage. This refers to a phenomenon where coinage not issued by the official authority was introduced into circulation and utilized in commercial exchanges of various kinds, a fact that can be demonstrated archaeologically. Imitative coinage can be detected through detailed numismatic studies, revealing variability in stylistic elements, as well as physical characteristics (such as weight or diameter) when compared to the official issue. Coin imitation should not be confused with monetary counterfeiting, as its intention was not to profit the unofficial issuer, but rather to facilitate daily commercial exchanges. Even so, the characteristics of both can be similar in some cases, which can make it difficult to assign them to one type or the other. The imitative pieces, primarily in bronze types though not limited to them, played a highly significant role in maintaining Roman economic systems during periods of decline in official currency.
Marc Bouzas Sabater (2026) studied this question.