Every US banknote carries two serial numbers that should be identical. Serial number errors occur when these numbers do not match, are printed in the wrong position, or contain other anomalies. Because serial numbers are applied during the third printing stage (overprinting), errors at this stage produce distinctive and collectible varieties.
Serial numbers are part of the "overprint" — the third and final printing pass that also applies the Treasury seal and Federal Reserve seal. Serial number errors happen when the overprint plates are damaged, misaligned, or when mechanical problems cause inconsistencies between the two serial number printings on each note.
Mismatched serial numbers are among the most valued overprint errors because they are dramatic and easy to verify. The extent of the mismatch matters — a single digit difference is worth less than multiple digits differing. Missing serials, inverted overprints, and dramatic misalignments also carry strong premiums. Condition and denomination affect pricing.
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Scan NowMismatched serials occur when the numbering wheels on the overprint press malfunction, skip, or are set incorrectly. One numbering head advances while the other does not, causing the two serial numbers on the same note to differ.
Yes. Notes with genuinely mismatched serial numbers are actively collected. Values range from $100 for single-digit differences to significantly more for multiple-digit mismatches or complete number changes.
Compare the two serial numbers on your note carefully, digit by digit. Also check that both are printed level and in the correct position relative to the Treasury seal and Federal Reserve seal.
Yes. Altering, defacing, or removing serial numbers on US currency is a federal offense. Only genuine, unaltered production errors have collector value.