| Horizon Air | airline | Seattle | 1981 |
| Horseshoe Las Vegas | casino, hotel | — | December 5, 1973 |
| Hotels.com | dot-com company, travel website | — | 1991 |
| House of Blues | restaurant chain, business, chain | Los Angeles | November 26, 1992 |
| Houston Grand Opera | opera company | Houston | 1955 |
| Howard University | historically black college or university, private not-for-profit educational institution, school, private university | Washington, D.C. | March 2, 1867 |
| HowStuffWorks | podcast network, business | Atlanta | July 11, 1998 |
| HubSpot | business, software development | Cambridge | 2006 |
| Hudson Motor Car Company | business, automobile manufacturer | Detroit | 1909 |
| Hudson Theatre | Broadway theatre, theatre building, movie theater | — | October 19, 1903 |
| Hughes Aircraft Company | aerospace manufacturer | Culver City, Los Angeles | 1932 |
| Hughes Airwest | airline | San Francisco International Airport | 1968 |
| Hughes Helicopters | business, enterprise | Mesa, Culver City | 1947 |
| Hult International Business School | business school, educational institution | — | 1964 |
| Humana | business, enterprise, public company | Louisville | 1961 |
| Humble Bundle, Inc. | video game publisher, digital book and audiobook distribution platform, digital distribution platform | San Francisco | March 1, 2010 |
| Huntington Bancshares | bank, business, financial institution, public company | Columbus | 1866 |
| Huntsman Corporation | business, enterprise, public company | Salt Lake City | 1982 |
| Hupmobile | business, automobile manufacturer | Detroit | 1909 |
| Hurley International | business, subsidiary company | Costa Mesa | 1998 |
| Hyperloop One | business | Los Angeles | June 2014 |
| Häagen-Dazs | food manufacturer, food brand, trademark, ice cream parlor chain | Oakland | 1961 |
| IBM | software company, multinational corporation, technology company, professional services firm, organization, business, enterprise, public company | Armonk | June 16, 1911 |
| IBM Research | business, laboratory | — | 1945 |
| Icahn School of Medicine at Mount Sinai | private not-for-profit educational institution, medical school | — | 1963 |
| Icon Comics | publishing house, company | New York City | 2004 |
| Idaho State University | public educational institution of the United States, public research university | — | 1901 |
| IDW Publishing | comics publishing company | San Diego | 1999 |
| IEEE Computer Society | publishing house, organization | Washington, D.C. | 1963 |
| IGN | online newspaper, online film database, business, video game news website | San Francisco | September 29, 1996 |
| IIT Institute of Design | graduate school, design school, higher education institution, academic institution | — | 1937 |
| Illinois Central Railroad | transport company | Chicago | 1851 |
| Illinois Tool Works | business, public company | Glenview | 1912 |
| Illumina | business, enterprise, company, public company | San Diego | 1998 |
| Illumination | film production company | United States, Santa Monica, Los Angeles, California | January 17, 2007 |
| Imagic | video game publisher, video game developer | Los Gatos | 1981 |
| Imagine Entertainment | television production company, film production company | Beverly Hills | November 1985 |
| IMG | business | New York City | 1960 |
| Immediate Music | record label, business | Santa Monica | 1993 |
| Impressions Games | video game developer | Cambridge | 1989 |
| Incyte | business, enterprise, public company | Wilmington | 2001 |
| Indeed | review site, search engine, business, employment website | Austin | November 2004 |
| Independent Moving Pictures | film studio, organization | New York City | 1909 |
| Indiana State University | public educational institution of the United States, public university | Terre Haute | 1865 |
| Industrial Light & Magic | television production company, film studio, business | San Francisco, Letterman Digital Arts Center | May 1975 |
| IndyMac | savings and loan association, business, credit institution | Pasadena | July 16, 1985 |
| Infinity Ward | video game developer | Woodland Hills | 2002 |
| Inflection AI | business, company | Palo Alto | 2022 |