With the closing of the United States Assay Office on December 14, 1853, there were no private firms minting gold coins in California. Gold bullion continued to arrive into the region with no place (the U.S. Mint in San Francisco would not open until April 3, 1854 with limited production for 2 years) for it to be coined into money.

Cashier John Kellogg and assayer G.F. Richter, formerly of the U.S. Assay Office under Curtis, Perry and Humbert, opened their firm on December 14, 1853. Kellogg, a former employee of Moffat & Co., was asked by several banking houses in San Francisco to mint private gold coins until the U.S. Branch Mint could go into production.

Their first coins were issued on February 9, 1854. $20 gold coins were minted through late 1855. A $50 coin was planned but was never issued for circulation. Augustus Humbert, the former U.S. Assayer, replaced Richter as a partner on April 24, 1855. The firm dissolved in 1860.