This Ultra-Rare Stamp Could Fetch a Record $5 Million at Auction

Get your stamp book ready for the ultimate addition.

This summer, Robert A. Siegel Auction Galleries is offering the William H. Gross Collection of United States Stamps. The organization is anticipating the collection will set a new high mark for stamps, estimating it will fetch $15 to $20 million in sales. Several stamps are expected to hammer down for more than $1 million, with the rarest being one of two known one-cent “Z” Grill stamps from 1868. If sold for its estimate of $4 to $5 million, the ultra-rare collectible would become the most valuable American postage stamp to date.

More from Robb Report

• A Rare 15-Carat Yellow Diamond Ring Could Fetch $1.2 Million at Auction This Spring

• Freddie Mercury's Former London Mansion Can Be Yours for $38 Million

• ModaMiami's First Auction Is Offering up $80 Million in Rare Cars, Motorcycles, and More Collectibles

So, what makes the “Z” Grill lot so special? After the Civil War, stamps were still relatively new, having debuted just two decades earlier. Fears arose about the potential to wash off cancellations from stamps and use them a second time. The potential loss of revenue from stamp-cleaning prompted the creation of patent methods that prevented their reuse.

One popular innovation to address potential reuse was a waffle-pattern embossing, known today as the “grill.” To achieve this effect, each stamp in a sheet was impressed with tiny pyramidal points that broke the paper’s surface. This allowed cancellation ink to seep into a stamp rather than sit on top of it, preventing reuse.

Stamp collections often share the goal of acquiring every stamp issued by the United States government. But given that one of “Z” Grill stamps was donated to the New York Public Library in 1925 and the other was owned by “Bond King” William H. Gross, no other U.S. stamp collection has been complete for the past 26 years.

Gross, the PIMCO co-founder, was initially outbid for the lot in Siegel’s 1998 auction of the Robert Zoellner collection. But in 2005, he was able to trade a 24¢ Inverted Jenny plate block for the “Z” Grill stamp, which experts called the “Greatest Stamp Swap of All Time,” Siegel claims in a statement. Other rare stamps such as the Alexandria postmaster’s provisional, the St. Louis Bears, the 24¢ Continental and the Inverted Jenny will join the “Z” Grill stamp at auction.

You can place your bids on the top 100 stamps from Gross’s prized collection at the Lotte New York Palace Hotel in New York City on June 14. The remaining stamps will be sold the next day at the Collectors Club of New York overlooking Bryant Park. If you can’t make the live sale, the Siegel firm is also providing telephone and internet bidding for the auction.

Best of Robb Report

• The 10 Priciest Neighborhoods in America (And How They Got to Be That Way)

• In Pictures: Most Expensive Properties

Sign up for Robb Report's Newsletter. For the latest news, follow us on Facebook, Twitter, and Instagram.

Click here to read the full article.