Posted 05/03/2020 4:54 pm
On $1 notes, prefixes represent the Federal Reserve Bank and only go A-L because there are 12 FRBs. The suffix letter doesn't mean anything specific, it's just part of the numbering.
Starting with Series 1996, all notes besides the $1 and $2 have another prefix letter in front of the FRB letter. This 2nd prefix letter indicates the Series (P=2017A, E=2004, A=1996, etc.). In theory with those notes you could have AAxxxxxxxxA, BBxxxxxxxxB, all the way up to LLxxxxxxxL, which would be pretty cool.
