A stamp known as the One-Cent Magenta from British Guiana was sold Tuesday for $9.5 million, the most any stamp has ever been purchased for at auction.
The telephone bidder wished to remain anonymous.
The 1 inch-by-1¼-inch stamp is the only known one of its kind. It is the "sole surviving One-Cent of the entire 1856 issue produced in Georgetown, British Guiana," according to the description from Sotheby's, the New York City auction house.
The stamp has an image of a boat with Latin words that can be translated as "We give and expect in return" and has a certificate of authenticity from the Royal Philatelic Society.
And perhaps as expected from such a small, expensive piece of paper, the One-Cent Magenta has a storied history.
The stamp was last in possession by multimillionaire chemical heir John E. du Pont, who died in prison in 2010 when he was 72 while serving a sentence for the murder of Dave Schultz, an Olympic freestyle wrestler.
(Schultz's story and death is recreated in the 2014 biopic Foxcatcher starring Steve Carell, Channing Tatum and Mark Ruffalo. Director Bennett Miller won top honors at this year's Cannes Film Festival.)
Prior to that, the stamp passed hands 10 times (including to the government of France from 1920-1922) and was exhibited at the 1940 New York's World Fair and international stamp conventions from 1923 to 1987.
"The significance of the stamp was first recognized by the great philatelist Edward Loines Pemberton, who declared as early as 1878 that the "ONE cent, red, 1856!!! (is) as genuine as anything ever was," reads the stamp's description.
The last stamp that drew similar recognition was the Treskilling Yellow, a stamp from Sweden that sold for $2.2 million in 1996 (which would be $3.3 million today), according to The New York Times.
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