One of just two known 1975 No-S proof Roosevelt dimes sold at the September 2019 Long Beach Expo for $456,000 (including 20% buyer's fee), making it one of the most valuable modern coins in the world. This example, sold by Heritage Auctions on September 6, 2019, is graded by Professional Coin Grading Service (PCGS) as PR68, making it the finest-known specimen.
This sale of this rare dime, which previously sold for $349,600 in 2011, was billed by Heritage Auctions as a "truly a once-in-a-lifetime opportunity to acquire one of the rarest issues in the U.S. federal series," and that claim is no hyperbole. The only other 1975 No-S Roosevelt dime known has been in the same collection for more than 40 years. That means many eyes were on this coveted error, an essential addition to any top-flight Roosevelt dime collection.
The 1975 No-S Roosevelt dime was discovered in 1975 by a California collector who ordered a set of five proof sets from the U.S. Mint. Two of those proof sets contained the 1975 No-S Roosevelt dime, and they were sold in the late 1970s to an Illinois coin dealer. The value of this particular specimen has skyrocketed over the years, as evidenced by the fact it sold for $38,550 in 1980 and realized more than $100,000 over what it took during its previous auction appearance just eight years ago.
There are several types of No-S Roosevelt proof dimes made when the obverse die somehow went into operation without receiving an "S" mintmark punch. These No-S Roosevelt dimes include the 1968 No-S, 1970 No-S, and 1983 No-S varieties. But the 1975 No-S Roosevelt proof dime is by far the rarest example of this class of errors. Perhaps other 1975 No-S Roosevelt dimes exist, but given the fact more than 40 years has elapsed since the two known specimens were found, the appearance of other examples seems highly unlikely. Any 1975 Roosevelt dimes you find in circulation without the "S" mintmark are regular-issue business strikes from the Philadelphia Mint and aren't supposed to contain any mintmark. If worn, these are worth face value.