- One of the most common questions we receive from many collectors has to do with a two-letter grading designation that PCGS
uses to boldly identify proof coins that were struck at branch mints. The PCGS
grade designation in question? It's "BM." This refers simply to "Branch Mint" Proof, and it's included on the labels of any PCGS
encapsulated coins that are proofs but were not struck at the Philadelphia Mint.
So, why does PCGS
call out proof coins that weren't struck at the Philadelphia Mint? While many collectors in recent decades may be perfectly accustomed to proof coinage being struck at, say, the San Francisco Mint, it wasn't always the case that proof coins were produced at United States Mint facilities beyond Philadelphia. In fact, until 1968, it was extremely uncommon for a proof coin to be minted anywhere else but the Philadelphia Mint.
When the first proof coins were struck in the United States during the early 19th century, they were produced at the Philadelphia Mint - then the only United States Mint facility. Over the decades that followed, Philadelphia remained the nerve center for all United States Mint coining as new mint facilities were established in the young and ever-expanding United States. Even today, the Philadelphia Mint is still regarded by many as the "mother mint." And for most of the first two centuries following the debut of the Philadelphia Mint in 1792, it remained the primary place for producing proof coinage.
However, that doesn't necessarily mean that all proof coins minted before 1968 hail from Philadelphia. There were several exceptions during which proof coins were produced at the branch mints to mark special occasions or to serve as presentation pieces. Some of the most popular Branch Mint Proofs include the following:
1876-CC Liberty Seated dime
1894-S Barber dime
1875-S Twenty Cent
1838-O Capped Bust half dollar
1893-CC Morgan dollar
Perhaps the most valuable of these is the 1894-S Barber dime
, which has a mintage of just 24 pieces and only nine known survivors. These coins regularly trade for seven figures.Barber Dime, 1894-S 10C, BM, PCGS PR66BM
While the Philadelphia Mint would almost exclusively strike proof coinage up into the mid-1960s, things changed in 1968. A major coin shortage that began around 1963 led to the United States Mint focusing virtually all its production efforts on striking coins for circulation, leading to a moratorium on proof coinage spanning from 1965 through 1967. By the time proof coinage resumed in 1968, production of most proofs was shifted to San Francisco.
In the years since, the Philadelphia Mint along with other facilities in the United States Mint network have manufactured proof coinage. Today, a proof coin being struck at the Denver, San Francisco, or West Point Mint is no longer an anomaly as it once would have been many decades ago. And, thus, it is because Branch Mint Proof coinage was at one time so unusual that it deserves separate recognition on PCGS
labels. Read More: Learn Grading Series