| King of the Cage | Rancho Cucamonga | 1998 |
| Kleiner Perkins | Menlo Park | 1972 |
| Knight's Armament Company | Titusville | 1983 |
| Knoll | East Greenville | 1938 |
| Koch Industries | Wichita | 1940 |
| Kohler Company | Kohler | 6 de dezembro de 1873 |
| Koss Corporation | Milwaukee | 1953 |
| Kroger | Cincinnati | 1882 |
| La Senza | Montreal | 1990 |
| La-Z-Boy | Monroe | 1927 |
| Lab126 | Cupertino | 2004 |
| Lear Corporation | Southfield | 1917 |
| Leatherman | Portland | 1983 |
| Legacy Fighting Championship | Texas, Estados Unidos | 2016 |
| Lehman Brothers | Nova Iorque | 1850 |
| Leidos | Reston | 1969 |
| Lennox International | Richardson | 1999 |
| Levi Strauss & Co. | São Francisco, Levi's Plaza | 1853 |
| Lime | San Mateo | janeiro 2017 |
| Linden Lab | São Francisco | 1999 |
| Lionel Corporation | Nova Iorque | 1900 |
| LJN Toys | Nova Iorque | 1967 |
| Loews Corporation | Nova Iorque | 1946 |
| Logitech | Lausana, Newark | 2 de outubro de 1981 |
| Lollapalooza | — | 1991 |
| Long Island Rail Road | Jamaica | 1834 |
| Lord & Taylor | Nova Iorque | 1826 |
| Lucasfilm Animation | São Francisco | 12 de maio de 2003 |
| Lycoming | Williamsport | 1845 |
| M&T Bank | Buffalo | 1856 |
| Mack Trucks | Allentown, Greensboro | 1900 |
| Macy's, Inc. | Cincinnati, Macy's Herald Square | 1929 |
| Manhattan Company | The Trump Building | 1799 |
| Manpower | Milwaukee | 1948 |
| MapQuest Inc. | Denver | 1967 |
| Marathon Oil | Houston | 1887 |
| Martin Marietta | Bethesda | 1961 |
| Massachusetts Mutual Life Insurance Company | Springfield | 1851 |
| Massey Ferguson | Duluth | 1953 |
| MasterClass | São Francisco | 2015 |
| Match Group | Kerrville | 2009 |
| Mattel | El Segundo | janeiro 1945 |
| McAfee | Santa Clara, São José | 1987 |
| McDonald's | Chicago | 15 de maio de 1940 |
| Mead Johnson | Glenview | 1905 |
| Memorex | Cerritos | 1961 |
| Mentor Graphics | Wilsonville | 1981 |
| Meraki | São Francisco | 2006 |