The Inverted Jenny (also known as an Upside Down Jenny, Jenny Invert) is a 24 cent United States postage stamp first issued on May 10, 1918, in which the image of the Curtiss JN-4 airplane in the center of the design is printed upside-down; it is one of the most famous errors in American philately. Only one pane of 100 of the invert stamps was ever found, making this error one of the most prized in philately.
A single Inverted Jenny was sold at a Robert A. Siegel auction in November 2007 for $977,500. In December 2007 a mint never hinged example was sold for $825,000. The broker of the sale said the buyer was a Wall Street executive who had lost the auction the previous month. A block of four Inverted Jennys was sold at a Robert A. Siegel auction in October 2005 for $2.7 million. In the wake of the 2008 financial meltdown, prices fetched by Inverted Jennys receded. Between January and September 2014, five examples offered at auction sold for sums ranging from $126,000 through $575,100. Prices eventually recovered, for on May 31, 2016, a particularly well-centered Jenny invert, graded XF-superb 95 by Professional Stamp Experts, was sold at a Siegel Auction for a hammer price of $1,175,000 The addition of a 15% buyer's premium raised the total record high price paid for this copy to $1,351,250. On 15 November 2018, the recently discovered position number 49 stamp was auctioned by Robert A. Siegel Auction Galleries for a new record hammer price of $1,350,000, with an 18 percent buyer's premium raising the total cost to $1,593,000.
Background
During the 1910s, the United States Post Office had made a number of experimental trials of carrying mail by air. These were shown by the first stamp in the world to picture an airplane (captioned as "aeroplane carrying mail"), one of the U.S. Parcel Post stamps of 1912–13. The Post Office finally decided to inaugurate regular service on May 15, 1918, flying between Washington, D.C., Philadelphia, and New York City. The Post Office set a controversial rate of 24 cents for the service, much higher than the 3 cents for first-class mail of the time, and decided to issue a new stamp just for this rate, patriotically printed in red and blue, and depicting a Curtiss Jenny JN-4HM, the biplane especially modified for shuttling the mail. The stamp's designer, Clair Aubrey Huston, apparently troubled to procure a photograph of that modified model (produced by removing the second pilot seat from the JN-4HT to create space for mailbags, and by increasing the fuel capacity). As only six such aircraft existed, there was a 1-in-6 chance that the very plane engraved on the stamp by Marcus Baldwin—Jenny #38262—would be chosen to launch the inaugural three-city airmail run; the plane on the stamp was indeed the first to depart from Washington on May 15, taking off at 11:47 a.m.
The job of designing and printing the new stamp was carried out in a great rush; engraving began only on May 4, and stamp printing on May 10 (a Friday), in sheets of 100 (contrary to the usual practice of printing 400 at a time and cutting into 100-stamp panes). Since the stamp was printed in two colors, each sheet had to be placed into the flat-bed printing press twice, an error-prone process that had resulted in invert errors in stamps of 1869 and 1901, and at least three misprinted sheets were found during the production process and destroyed. It is believed that only one misprinted sheet of 100 stamps got through unnoticed.
Many collectors long thought the blue plane portion was printed first, thus it was actually the red frames that were inverted. In fact, the frames were printed first and it is the planes that are upside down. In examples where the plane is so far off center that it overlaps the frames, it can be seen that the blue ink used to print the plane lies atop the red ink used to print the frames. The Smithsonian's National Postal Museum offers two explanations for how this might have occurred: either a sheet of printed frames was placed in the press upside down for the printing of the plane; or the printing plate used to print the planes was mounted inverted within the printing press.