The finest known 2c Pan-American invert has smashed its estimate at a postage stamp auction.

The fabled stamp sold for $170,000 against a $55,000 valuation at yesterday's Hanover Collection of Superb Quality US Stamps sale at Robert A Siegel in New York.

The finest of the 64 known error singles

With its full original gum, it is the only one of the 64 surviving error singles to have achieved a grade of "Superb 98".

The six Pan-American denominations were unveiled at the 1901 Pan-American Expo in Buffalo, New York, with each depicting a different form of modern transport.

Aside from the stamps, the Pan-American Expo was notable for the assassination of President William McKinley within the grounds.

The sale also featured an inverted example of the 4c Pan-American stamp. Graded "Extremely Fine 90", it sold $20,000 above estimate for $105,000 - testament to its rarity in high grades.

A 1917-1919 2c deep rose also sold for a significant sum.

Described by Siegel as "an outstanding rarity and one of the rarest stamps of 20th century United States philately," it achieved $45,000.

The US Bureau of Engraving and Printing delivered the stamp to the Schermack Company for use in its stamp affixing machine.

It's one of 34 used specimens of the 40 surviving examples.

It features the Schermack machine's type III perforations, which, unusually, have not cut into the design here.

View our superb range of stamps for sale here.

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