In the context of paper money collecting, the term “mule” may breed a degree of confusion. A mule note is typically one that uses a face plate or back plate that is associated with a different series imprint or signature combination. In comparison, this is not nearly as apparent as a coin that may be considered a “mule.”
The practice was particularly widespread during the early 1920s as a cost-cutting measure at the Bureau of Engraving & Printing. Shortly after Treasurer Frank White assumed office in 1921, new back plates were engraved on which the position of the plate indicator was moved from its previous position.
The Bureau, which did not casually discard perfectly good plates, used both the old and new plates simultaneously resulting in the mules that are often encountered at auction. These pieces from the early 1920s were printed from back plates engraved during the tenure of White’s predecessor John Burke who held office from 1913 to 1921, while the face plates were more recent creations engraved after White assumed the responsibilities of treasurer in 1921.
The mules of the 1920s were by no means the last to be produced, as such notes were made in quantity under the Series of 1934 and Series of 1934A. These mules can be discerned by a small-sized (micro) plate number and a large-sized (macro) plate number on opposite sides of the note. They are often overlooked by collectors, although some specialists pursue these notes with strong interest.
Mule notes representative of various denominations and series dates are often featured in our monthly Collectors Choice Online (CCO) auctions or our showcase auctions, including our upcoming Spring 2025 Showcase Auction.
For more information about our auctions or to consign your numismatic items, please call 800-458-4646 or email [email protected].
