Stamp swap caps collection

NEW YORK (AP) — In a multimillion-dollar swap, a California collector traded a block of four 1918 stamps bearing the image of an upside-down plane Wednesday for an equally rare 1868 one-cent stamp.

The blockbuster transaction filled out what experts believe is the only complete collection of 19th-century U.S. stamps.

The block of four stamps is valued at $3 million, and the single "Z Grill" stamp is similarly valued.

"The 'Z Grill' is like the Holy Grail of U.S. stamps — it's the Hope diamond of American philately," said Charles Shreve, president of Shreves Philatelic Galleries in Manhattan.

At the heart of the deal is Bill Gross of Newport Beach, Calif., who was missing the one-cent "Z Grill" stamp owned by Donald Sundman, president of Mystic Stamp Co. of Camden, N.Y.

Gross now has "a comprehensive, complete collection representing every 19th-century U.S. postage stamp ever made," Shreve said. The collection contains about 300 stamps.

Small, blue-hued and bearing the image of Benjamin Franklin, the "Z Grill" is so named because of the waffle-like grill pressed into the back that better absorbed postmarks and prevented people from washing off the cancellation and reusing the stamp.

It's one of only two existing "Z Grill" stamps; the other is owned by The New York Public Library.

Sundman said he plans to show his "Inverted Jenny" stamps at exhibitions around the country. The 24-cent stamps have the Curtiss JN-4 biplane, known as "Jenny," mistakenly printed upside-down.

Gross was not present Wednesday and would not immediately comment on the trade. He plans to exhibit his newly acquired "Z Grill" in May at the National Postal Museum, part of the Smithsonian Institution in Washington, at the same time the "Inverted Jenny" will be displayed there, Shreve said.