The 1921 Mercury dime is a popular semi-key date with the third-lowest mintage of the series, behind the 1921-D (second) and 1916-D (first). This issue's low mintage, barely above 1.2 million, was in part due to a mild recession that had set in following World War I. Also, the United States Mint was focusing a great deal of its production effort toward making silver dollars in 1921.

For the most part, 1921 Mercury dimes were not saved in huge numbers by collectors. And with relatively few to begin with the surviving quantity of Full Bands examples simply was not very high. In total, there are only a few hundred Mint State examples with full details in the horizontal bands across the fasces on the reverse. In grades above MS66FB, the 1921 is a true rarity. One PCGS/CAC example graded MS67 went for $32,200 in a 2010 Heritage Auctions event. <>BR>
Beware of altered-date or counterfeit specimens, as well as authentic 1921 Mercury dimes with the bands artificially split -- something that is sometimes done with a tool as simple as a sharp pen knife. Unless skilled with spotting fakes and key diagnostics on real coins, opt for third-party-graded specimens of this coin whenever possible.