| Thinking Machines Lab | — | 2025 |
| Thrustmaster | Hillsboro | 1990 |
| THX | São Rafael | 1983 |
| Tiger Electronics | Vernon Hills | 1978 |
| Timberland | Stratham | 1952 |
| Time Inc. | Nova Iorque | 28 de novembro de 1922 |
| Titleist | Fairhaven | 1932 |
| TKO Group Holdings | Nova Iorque | 12 de setembro de 2023 |
| Todd-AO | Hollywood | 1953 |
| Tommy Hilfiger | Nova Iorque, Amsterdã | 1985 |
| TopCoder | São Francisco | 2001 |
| Total Nonstop Action Wrestling | Nashville | 4 de janeiro de 2024 |
| Tower Records | Sacramento | 1960 |
| Tractor Supply Company | Brentwood | 1938 |
| Transmeta | Santa Clara | 1995 |
| Traxxas | McKinney | 1986 |
| Trek Bicycle Corporation | Waterloo | 1976 |
| Trident Microsystems | Santa Clara | 1987 |
| Trimble | Westminster | 1978 |
| Tripadvisor | Needham | 14 de fevereiro de 2000 |
| Truist Financial | Charlotte | 1872 |
| Trump University | Nova Iorque | 2005 |
| Trumpet Records | — | 1951 |
| TRW Automotive | — | — |
| TRW Inc. | Euclid | 1901 |
| Turner Construction | Nova Iorque | 1902 |
| Turner Entertainment | Estados Unidos | 4 de agosto de 1986 |
| Turnitin | Oakland | 1997 |
| U.S. Bancorp | Minneapolis | 1850 |
| Ubiquiti | Nova Iorque | outubro 2003 |
| UGG | Goleta | 1978 |
| Ulta Beauty | Bolingbrook | 1990 |
| Ultimate Ears | Irvine | 1995 |
| Under Armour | Baltimore | 1996 |
| Underwood Typewriter Company | Nova Iorque | 1875 |
| Union Carbide | Danbury | 1957 |
| Union Iron Works | São Francisco | 1849 |
| Unisys | Blue Bell | 1987 |
| United Fruit Company | Fort Lauderdale, Étoy | 30 de março de 1899 |
| United Parcel Service | Sandy Springs | 28 de agosto de 1907 |
| United Press International | Washington, D.C. | 1907 |
| United States Playing Card Company | Erlanger | 1867 |
| United States Wrestling Association | Memphis | 1989 |
| United Technologies Corporation | Hartford | 1929 |
| Unity Technologies | São Francisco | 2 de agosto de 2004 |
| Unocal Corporation | Los Angeles | 1890 |
| Upjohn | Michigan, Kalamazoo | 1886 |
| Uproxx | Culver City | 2008 |