What Does the BM Grading Designation Mean?

The grading designation “BM” comes up frequently when dealing with vintage proof coins, and it leaves many collectors to wonder what this acronym means and why it’s used only on some proof coins. As the PCGS Lingo webpage defines BM, “The designation BM refers to ‘Branch Mint,’ meaning any U.S. Mint other than Philadelphia. You will usually find this designation used to describe Branch Mint Proof coins, such as the 1879-O BM Proof Morgan dollar, 1893-CC BM Proof Morgan dollar, etc.”

Some collectors may be somewhat taken aback by this designation, specifically where it describes the BM designation meaning proof coins struck beyond Philadelphia. Many would wonder why special grading nomenclature is needed for proofs struck outside of Philadelphia, especially when proofs are customarily struck at the branch mints of San Francisco and West Point. If anything, Philadelphia proofs seem to be the exception these days. Except, it wasn’t always that way.

Before the late 1960s, the Philadelphia Mint was the given origin for proof coins – virtually all proofs made for collectors, presentation purposes, or other reasons were made in the City of Brotherly Love. And that’s exactly why the BM designation is so important when labeling proof coins; so few proof issues emanated from anyplace other than Philly before regular proof production was relocated to San Francisco in 1968.

Therefore, there is little numismatic need for calling out contemporary proofs from San Francisco, West Point, or even Denver on occasions as warranted, as “BM” branch mint proofs. Yet, when we look back on the short by prestigious list of coins officially classified by PCGS as branch mint proofs, you can see just how significant some of those pieces are – both in terms of rarity and in the context of why they deserve special recognition.

Here’s a partial list of coins that PCGS recognizes as branch mint proofs:

• 1894-S Barber Dime Proof BM
• 1838-O Capped Bust Half Dollar Proof BM
• 1879-O Morgan Dollar Proof BM
• 1893-CC Morgan Dollar Proof BM
• 1844-O Liberty Head Half Eagle Proof BM

Branch mint proofs, as defined by those struck prior to the late 1960s, are not only extraordinarily rare and valuable, but they are also historically significant either by way of the reason they were struck or the importance they hold in numismatics. As further research reveals new branch mint proofs, there may be new coins that qualify for the BM grading designation.