- Abilene Flour Mills Co.1
- Abner Harvey Duncan, trading as the Smith Medicine Co., St. Louis, Mo.1
- Ace High Products Co.1
- Acme Salt Co., Inc.1
- Adam Kissner, St. Louis, Mo.1
- Adam Roth Grocery Co.1
- Adams Laboratories, Inc.1
- Adolph Goldniark & Sons, Inc.1
- Agmel Corp1
- Agmel Corp.1
- Akin Products Co.2
- Albany Canning Co.1
- Albert J. Stoll, trading as Stoll Candy Company1
- Albert Kinder1
- Albert W. Anderson, Swing, Mo.1
- Alf Wilson, Hamburg, Ill.1
- Allaire Woodward & Co.1
- Allan & Co., Inc., St. Louis, Mo., and John G. Ayars1
- Allan Pfeiffer Chemical Co.1
- Allan-Pfeiffer Chemical Co., a corporation, St. Louis, Mo.1
