Symbols in Serial Numbers

Serials on the earliest large-size notes were simple numbers, with no letters or symbols around them. By 1869, however, serials were given a letter (or rarely, symbol) prefix and a symbol suffix as a security measure, to prevent alteration of the serials by adding digits. The letter prefix also allowed for a larger number of different serials to be printed, as the letter could be changed periodically to create new serial number blocks.

As the volume of currency issued increased, printings eventually became so large that an entire alphabet of prefix letters was not sufficient to give enough distinct serials for all the notes. Thus, letter suffixes began to be used as well, in place of symbol suffixes. The first use of a letter suffix was on 1882 $5 Nationals in 1899. After about 1913 the use of a letter as suffix became standard on new series, though some older series that remained in production continued to use symbol suffixes through the end of the large-size era.

When star replacement notes were introduced in 1910, they were given a star prefix and a letter suffix. These are the only notes to use a letter as suffix but not as prefix. Indeed, at the time they were introduced, they were the only notes other than Nationals to use a letter suffix at all, as no other types began to use two-letter serials before about 1912. Of course, when Federal Reserve currency was introduced in 1914, its prefix letters had specific meanings, so the replacement star had to be moved to the suffix position on these notes. No ambiguity resulted, since the regular notes of these types were using a letter suffix, not a symbol.

On Nationals, only the Treasury serial ever used a suffix symbol or letter; the bank serial remained without a suffix throughout the large-size era.

In all, some 21 different symbols were used in serials on large-size notes. The table below shows these various symbols, in approximate order of first use, and lists the series on which each appears.

Symbol	Series Used
	Original Series NBNs, printings after mid-1869 (occasionally as both prefix and suffix) 1863 USNs, very late $500 and $1000 printings (as both prefix and suffix; only on left serial) 1870-1875 GCs
	1869 USNs 1890-1891 CNs Very early star replacement notes in 1910 (known only on 1899 $1 SC)
	1874 USNs, $1 and $2 only 1875 USNs, $1-$10 only
	1874 USNs, $50 and $500 only 1879 RCs, very early printings (payable to order)
	1875 USNs, $20-$500 only
	1875 NBNs
	1878 USNs
	1878 SCs
	1879 RCs, most printings (payable to bearer)
	1880 USNs, printings before about 1884
	1880 SCs, printings before about 1884
	1882 NBN brownbacks (but some of these use a letter suffix) 1891 SCs, $20 and $50 printings after about 1913
	1882 GCs 1922 GCs, $100 and $500 only (the exact shape of this symbol is quite variable over time)
	1880 USNs, printings after about 1884 (but some very late $20 printings use a letter suffix)
	1880 SCs, printings after about 1884
	1886 SCs
	1891 SCs, except a few late printings after about 1913
	1896 SCs (as both prefix and suffix) 1905-1913 GCs (some 1905 as both prefix and suffix) 1922 GCs, except $100 and $500 1902 NBN datebacks and plainbacks (but some use a letter suffix, and others lack Treasury serials entirely)
	1899-1908 SCs (some 1899 as both prefix and suffix; some $1 printings use a letter suffix) 1901-1907 USNs (some 1901 as both prefix and suffix) 1902 NBN redseals 1882 NBN datebacks and valuebacks
	1900 GCs
	Star replacement notes, except a few very early printings

Since no examples survive, it is unknown what symbols were used as serial suffixes on the 1888 GCs and 1872-1875 CCs; it is possible that they were different from all of the symbols in the table.