David Akers (1975/88): The 1889-CC is neither one of the rarest issues from the Carson City Mint nor is it one of the most common. It is right in the middle of the pack, similar overall to the 1877-CC, 1882-CC and 1892-CC. When available, the 1889-CC can be in any grade from VF to AU and average quality uncs, while certainly very scarce, are also seen from time to time. Choice mint state specimens are rare and gems are very rare.
It's time (2016) to take another look at the 1889-CC $20. The PCGS Population Report shows totals for all of the CC-Mint Liberty Head Double Eagles. Where once the 1889-CC was considered "middle of the pack" in terms of overall rarity, it is now considered one of the most common dates among the CC Twenties -- the "most common" spot is now shared with the 1876-CC, the 1889-CC, and the 1890-CC. The 1884-CC and the 1875-CC come close, but most of the other CC-Mint Twenties have considerably smaller populations.
As plentiful as the 1889-CC may be, it is difficult to find nice ones. Most Mint State 1889-CC's are low-end Uncs., usually no better than MS62. PCGS has certified a small number of MS63 examples, but only a single MS64. The key to collecting this date is to seek examples that are as free of bagmarks as possible.
Heritage 2/2011:4656, $27,600