Three sisters finally sell rare coin with a missing mint mark for a whopping $500,000 following decades of it being locked up in a family vault

The sisters in Ohio had gained access to the dime, which their late brother had kept it in a bank vault for over 40 years, once he'd died.

Three sisters in Ohio have finally sold a rare coin with a missing mint for a whopping $500,000 following decades of it being locked up in a family vault.

The sisters gained access to the dime, which their late brother had kept in a bank vault for over 40 years, once he’d died. The coin features President Franklin D. Roosevelt on its obverse and was struck by the U.S. Mint in San Francisco in 1975, but the error coin was only discovered in the 1970s.

It’s extraordinarily rare because it makes up just one of two known coins to exist without an S mint mark - to reflect where it was made.

The sisters, who chose to be anonymous, told a California auction house that their brother and mom bought the error coin in 1978. They forked out a sum of $18,200 for the exclusive coin - roughly equating to $90,000 today.

Their parents operated a dairy farm and saw the coin as a financial safety net. Their brother opted to secure the prized coin in a bank vault so the family could use it as a rainy day fund if the need ever arose.

The sisters went on to pocket an astonishing $506,250 in an online auction on Sunday, according to Ian Russell, president of GreatCollections, an auction house based in Irvine, California.

The only other known example of the 1975 no S proof dime was sold at a 2019 auction for $456,000 before being resold to a private collector months later.

The San Francisco mint made more than 2.8 million special uncirculated proof sets in 1975 that featured six coins and were sold for $7. Collectors a few years later discovered that two dimes from the set were missing the mint mark.

It comes after a 1837 Seated Dime sold for $3,750 in October - and could be worth even more under the right circumstances. The 1837 Seated Dime marks a significant chapter in American coinage, being part of the Seated Liberty series that ran from 1837 to 1891.

The coin’s "No Stars" variety is particularly valuable because of its limited mintage period, Heritage Auctions reports. It was struck only at the Philadelphia Mint in 1837 and the New Orleans Mint in 1838. Coins from these early mints are rare, and this dime's exceptional state makes it a coveted find for collectors.