The Ninth Series includes stamps issued over five years in three groups.
1915 Panama National Exposition Issue
Panama ordered eight denominations to commemorate the 1915 Panama National Exposition and the opening of the Panama Canal in 1914, the ½ c, 1c, 2c, 2 ½ c, 3c, 5c, 10, and 20 c stamps. The Panama Canal Administration requested that a small portion of these stamps, the 1c, 2c, 5, and the 10c be overprinted for use in the Canal Zone. Panama placed its own order with the ABNCo together with an order for the Canal Zone.