| Lexmark | Lexington | 27 de março de 1991 |
| Liberty Media | Condado de Douglas, Colorado | 1991 |
| Linden Lab | São Francisco | 1999 |
| Line 6 | Calabasas | 1996 |
| Lionel Corporation | Nova Iorque | 1900 |
| LJN Toys | Nova Iorque | 1967 |
| Loews Cineplex Entertainment | Nova Iorque | 1910 |
| Logitech | Lausana, Newark | 2 de outubro de 1981 |
| Lollapalooza | — | 1991 |
| Lonely Planet | Melbourne | 1972 |
| Long-Term Capital Management | Greenwich | 1994 |
| Lucasfilm Animation | São Francisco | 12 de maio de 2003 |
| M-Audio | Cumberland | 1998 |
| Mack Trucks | Allentown, Greensboro | 1900 |
| Macy's, Inc. | Cincinnati, Macy's Herald Square | 1929 |
| Mailchimp | Ponce City Market | 2001 |
| Malpaso Productions | Burbank | 1967 |
| Malwarebytes | Santa Clara | 21 de janeiro de 2008 |
| Manpower | Milwaukee | 1948 |
| MapQuest Inc. | Denver | 1967 |
| Marathon Oil | Houston | 1887 |
| Marriott Internacional | Bethesda | 8 de outubro de 1993 |
| Marsh & McLennan Companies | Nova Iorque | 1905 |
| Massachusetts Mutual Life Insurance Company | Springfield | 1851 |
| Masten Space Systems | Mojave | 2004 |
| Matson, Inc. | Honolulu | 1882 |
| Mattel | El Segundo | janeiro 1945 |
| Maytag | — | 1893 |
| McAfee | Santa Clara, São José | 1987 |
| McDonald's | Chicago | 15 de maio de 1940 |
| McGraw-Hill Education | Nova Iorque | 1888 |
| McKesson Corporation | Irving | 1994 |
| Mead Johnson | Glenview | 1905 |
| Meade Instruments | Irvine | 1972 |
| Mercury Marine | Fond du Lac | 1939 |
| Meredith Corporation | Des Moines | 1902 |
| Merrill Lynch | Nova Iorque | 6 de janeiro de 1914 |
| MetLife | Nova Iorque | 24 de março de 1868 |
| Micro Instrumentation and Telemetry Systems | Albuquerque | 1970 |
| MicroStrategy | Tysons Corner | 1989 |
| Midway Games | Chicago | 1988 |
| Milton Bradley Company | East Longmeadow | 1860 |
| Missouri Pacific Railroad | St. Louis | 1917 |
| Mistwalker | Tóquio, Japão, Honolulu | 2004 |
| MITRE Corporation | Bedford | 1958 |
| Modulus Graphite | Richmond | 1978 |
| Mondelēz International | Chicago | 2012 |
| Monster | Guaynabo | 1999 |