In total, there are 6.4 million pairs of $1 bills with matching serial numbers. Neither misprint was caught by the US Bureau of Engraving and Printing, and now currency collectors are clamoring to find matching pairs of dollar bills with these duplicate serial numbers. Typically, every bill in circulation has a unique serial number to identify it.

This miscommunication resulted in dollars printed with duplicate serial numbers, technically counterfeiting their currency. In July 2016, the exact same request was sent to the Fort Worth facility. In November 2014, the US Bureau of Engraving and Printing sent a request to its Washington DC facility to print a batch of dollar bills. Over 6 Million Misprinted $1 Bills in Circulation Is Your One Dollar Bill Worth Real Money?.What To Do If You’re the Lucky Owner of One of the Misprinted Bills.How To Identify Bills Worth Up to $150,000.Over 6 Million Misprinted $1 Bills in Circulation.