- John Ewan, Silversmith1
- John Reynders & Company, New York/Chicago1
- John Wyeth & Brother, Philadelphia, Pennsylvania1
- Johnson Bros, England1
- Josten1
- Kays Caps Inc. Green Island, NY1
- Kny-Scheerer Company, New York1
- Kouwenhoven, William B., M.D.1
- Kredel, Frederick E. (1903-1961)1
- Lamberton Scammell, China1
- Lentz & Sons1
- Leonard, C. Henri (Charles Henri) 1850-?1
- Lucae, Johann Constantin August 1835-19111
- Lundborg1
- M.U.S.C.1
- MCSSC1
- MIZZY Incorporated, Clifton Forge, VA1
- MacGregor Instrument Co., Needham, MA1
- Mager & Gougelmann, New York, NY1
- Marshall1