The one-of-a-kind 1855 misprint was sold to a group of buyers who asked that their identities and the winning bid be kept confidential, said auctioneer David Feldman.
He declined to reveal whether the sale matched the 2.875 million Swiss francs (then about $2.3 million) price it set a record for in 1996.
“It is still worth more than any other single stamp” including the even older “2 Penny Post Office Mauritius Blue” that sold for 1.5 million francs (then $1.4 million) in 1993, said Feldman.
The auction house valued the stamp at euro1.5 million to euro2 million ($1.87 million to $2.5 million) before the sale, but actual sales prices can vary greatly depending on what the buyers feel such unique items are worth.
Feldman told the AP that Saturday’s auction “happened very quickly because the buyers clearly knew how much they were prepared to pay.”
The economic downturn has made people more careful about bidding for such pricey items, he said. At the same time, stamps are increasingly being seen as investment opportunities, he added. “People are looking for investments they can hold in their hands.”
The Treskilling Yellow has changed hands at least once since 1996, but little is known about the last owner except that he or she had to sell the stamp because it had been put up as financial collateral.
The first collector to own the stamp is said to have been a Swedish schoolboy, who found it in 1885 among a pile of letters left by his grandparents. A similar tale is told about the 1 cent Magenta.
Feldman said the Treskilling Yellow was last displayed in public a week ago at the London 2010 Festival of Stamps.