Jaime Hernandez: For modern coins issued from 1965 to date, the Proof 1990 No S Lincoln cent is considered a beast, to say the least.
Primarily because less than 200 examples exist. It is from an extremely dynamic and popular series. It is the only proof coin from 1909 to 2009 or in the entire Lincoln cent series, which is missing the extremely significant mint mark. The coin exist against all odds. Moreover, the missing mint mark is clearly transparent, even with the naked eye.
First of all, in 1985 the U.S. Mint abandoned the practice of punching mint marks on to working coin dies and instead, it began punching the mint mark directly on to the working hubs. However, the 1990 No S Proof Lincoln cent was inadvertently struck by a mint state die which was accidentally treated like a proof die.
This occurred since the Mint inadvertently shipped a mint state die to the San Francisco Mint without the die containing the S mint mark. This mint state die was then polished, sand blasted, struck several times and remarkably, it was then transformed into a proof die, or what I like to call a beast! Amazingly, the 1990 No S Proof Lincoln cents deceived both the Philadelphia and San Francisco Mints.
The 1990 No S Lincoln cents were first discovered on July 18, 1990 by Jim Gullen of New York. Following the discovery, the U.S. Mint publicly announced that several 1990 Proof Lincoln cents with missing mint marks were accidentally struck at the San Francisco Mint. The Mint also confirmed the destruction of 145 examples of the 1990 No S Proof Lincoln cents.
The 1990 No S Proof Lincoln cents were found in regular 1990 Proof Sets as well as being found in 1990 Prestige Proof Sets. At the time, the Mint was producing approximately about 3,700 proof Lincoln cents from each pair of dies. Therefore, in the early 1990's most collectors and dealers had the notion that thousands of 1990 No S Proof Lincoln cents existed. However, time would contradict these figures and prove otherwise, since less than 200 coins have surfaced.
The estimate of less than 200 coins existing is due to the simple fact that these coins are seldom encountered. For approximately 20 years, the approximate figure of fewer than 200 coins extant has remained somewhat stable. For years, there have not been any reports of more 1990 No S Proof Lincoln cents being discovered. The majority of 1990 Proof and Prestige sets have been inspected. Dealers, collectors and cherry pickers of both modern and classic coins are well aware of this variety, especially, since it commands thousands of dollars even in the lowest grades. Lastly, this coin is hardly encountered in any major dealers inventory or even at some of the major auctions, where only a few examples make an appearance every year.
The 1990 Proof Lincoln cent with the No S mint mark is also amidst several other proof No S mint mark coins. These include the 1976 No S Eisenhower Dollar, the 1968, 1970, 1975, and 1983 No S dimes. Also the 1971 No S nickel.
All seven different proof No S coins have always been very popular and have always commanded huge premiums. Completing a set of proof No S coins is practically impossible. Primarily, because there is only one 1976 Proof No S Ike known. The 1976 No S proof Ike is the scarcest of all the No S proof coins. The 1975 no S dime is the second scarcest, with two examples known. The 1968 No S Dime being the third scarcest, with only about a dozen examples known. Finally, the 1990 No S Lincoln cent being the third scarcest of the No S coins, with less than 200 examples known.