The 1918/7-S is the leading rarity among Mint State Standing Liberty quarters, surpassing even the key date 1916. An overdate whose mintage is included in the 11,072,000-piece total reported for the 1918-S, the number of examples produced will never be known. Numismatic scholars account for fewer than 1,000 survivors in all grades, leading J.H. Cline (Standing Liberty Quarters, Fourth Edition, 2007) to speculate that only 2,500 or so examples were struck. Typically offered in circulated grades, and well worn at that, the 1918/7-S is a major rarity in Mint State. The overdate feature was not recognized until 1937, by which time most examples had long since entered commercial channels. Only a handful of Full Head coins are included among the Uncirculated survivors, and they are eagerly sought by advanced specialists in this challenging 20th century quarter series.

The example to the left was sold by Stack's Bowers Galleries in the Larry H. Miller Collection, where it realized $102,000.