Error Note Chronicles: Mismatched Prefix Error

Posted on 8/16/2022

Mistakes don't just happen with the numbers in a banknote's unique identifier.

Paper Money Guaranty® (PMG®) is the world’s leading authority on banknote errors, a popular segment of numismatics. In Error Note Chronicles, we take an in-depth look at different errors. This month’s topic is the Mismatched Prefix Error.

It is standard procedure with currency printing to include the serial number in multiple locations on the banknote. Many notes, including US ones, have a prefix letter that accompanies the digits in the serial number. When the numbering wheels are accidentally set to different numbers, a Mismatched Serial Number Error occurs. When the prefix letters don't match, a Mismatched Prefix Error occurs.

US Currency includes letters at the beginning and end of the serial number. Through the 1995 Series, the prefix was a single letter from A through L that corresponded with one of the 12 Federal Reserve Bank around the country. More recently, all denominations above $2 now include a two-letter prefix: the first for the series and the second for the Federal Reserve Bank.

This 1976 $2 Federal Reserve Note (New York) has a Mismatched Prefix Error. The right prefix is B, which corresponds to the note's black seal for the Federal Reserve Bank of New York. But the left prefix is H, the letter used by the Federal Reserve Bank of St. Louis. (This note is being offered in a Heritage Auctions sale this month.)

1976 $2 Federal Reserve Note (New York) with a Mismatched Prefix Error graded PMG 66 Gem Uncirculated EPQ
Click images to enlarge.

This error can occur on world banknotes, as well. This Japan 2,000 Yen Commemorative has a Mismatched Prefix Error, in which the prefix on the left is J and the one on the right is L. These notes, worth about $15, are occasionally seen in circulation in Japan, making them similar to the US $2 note. This particular error note sold for $1,800 at a Heritage Auctions sale in December 2020.

Japan, Bank of Japan ND (2000) 2,000 Yen Commemorative with a Mismatched Prefix Error graded PMG 68 Superb Gem Unc
Click images to enlarge.

An error can also occur when the letters at the end of the serial number do not match. This 1999 $1 Federal Reserve Note has a Mismatched Suffix Error. This type of error is much less common than the Mismatched Prefix Error, and this particular note realized $1,620 in a Heritage Auctions sale in January 2021.

1999 $1 Federal Reserve Note (Philadelphia) with a Mismatched Suffix Error graded PMG 40 Extremely Fine
Click images to enlarge.

PMG, an independent member of the Certified Collectibles Group® (CCG®), has certified many exciting error notes, including the famous “Del Monte” error note that realized $396,000 in a January 2021 sale.

Collectors and dealers with error notes can submit them to PMG for certification under an applicable grading tier with “error” or the specific error noted under the Variety/Pedigree column on the submission form. There is no additional fee for this service.

For more information about submitting to PMG, visit

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