The Panama Pacific Expo, held in 1915, was meant to celebrate the completion of the Panama Canal. However, despite its official purpose, this world’s fair was widely seen as an opportunity to showcase San Francisco’s remarkable recovery from the 1906 earthquake. The expo was a tremendous success, but its commemorative coinage was an initial failure. Relatively few of the gold and silver coins sold during the fair and many of the excess specimens were melted. Decades later, however, these “commems” became wildly popular—and valuable.

Five different commemorative coins were introduced for the expo: a silver half dollar, a gold dollar, a gold quarter eagle and two $50 gold pieces. The half dollar, being a more affordable coin, sold the best of the batch. A total of 60,000 pieces were made of which 27,134 found buyers. While fewer than half of the total mintage was sold, its total sale eclipsed that of the gold issues.

The 1915 Panama Pacific gold dollar had a total mintage of 25,000 pieces but just 15,000 were sold. The balance was melted. The quarter eagle, meanwhile, had a modest mintage of 10,000 with just 6,749 pieces sold to collectors. The worst sellers, both in percentage and absolute terms, were the two $50 gold pieces offered for sale: the round-shaped and octagonal-shaped “slugs.”

Containing over two ounces of gold and carrying a face value of $50, promoters knew that very few of these massive gold coins would be sold. They only struck 1,500 pieces of each format accordingly. Despite the modest mintages, the coins still failed to sell out. Just 645 of the octagonal coins were distributed and a paltry 483 “rounds” were sold to the public. Numismatists speculate that the octagonal version sold better due to their unique shape.

Towards the mid-20th century, the Panama Pacific Exposition commemorative coins began to gain respect (and value) as scarce, beautiful collectibles. Today, the pieces can command tremendous premiums. The silver half dollars sell for a minimum of $500-$750 in lower grades with Gem Uncirculated specimens commanding $1,500-$2,500. The gold dollars trade for similar levels. Meanwhile the quarter eagles are worth a minimum of $1,500-$2,000 in low-end Uncirculated with Gem-quality pieces fetching upwards of $5,000.

As valuable as the smaller denominations are, the $50 gold pieces are by far the most valuable of the Panama Pacific commems. At a minimum, even if lightly worn or cleaned, these massive gold coins command prices in the $30,000-$50,000 range today. Being such large coins they are prone to picking up scratches and marks—therefore Gem Uncirculated specimens are extremely rare. One can expect to spend upwards of $100,000 for Gem pieces with the very best coins trading for close to $200,000!