| Saber Interactive | video game developer | Fort Lauderdale, Minsk, Sundsvall, Porto, Millburn, Community of Madrid, Saint Petersburg, Florida | 2001 |
| Saint Anselm College | private not-for-profit educational institution, liberal arts college in the United States | Manchester | 1889 |
| Saint Joseph Higher Secondary School | college | — | 1954 |
| Saint Joseph's University | private not-for-profit educational institution, university | — | 1851 |
| San Francisco Art Institute | private not-for-profit educational institution, art academy, private university | San Francisco | 1961 |
| Sanmina Corporation | business, public company | San Jose | 1980 |
| Santa Barbara City College | community college, public educational institution of the United States, school | — | 1909 |
| Santa Clara University | private not-for-profit educational institution, university | Santa Clara | 1851 |
| Santa Monica College | community college, college, public educational institution of the United States | Santa Monica | 1929 |
| Santa Monica Studio | video game developer | Playa Vista | 1999 |
| Sara Lee Corporation | business, enterprise | Downers Grove | 1939 |
| Saucony | business, subsidiary company | Lexington | 1898 |
| Sbarro | fast food restaurant chain, pizzeria chain, company | Huntington | 1956 |
| Scaled Composites | aerospace manufacturer | Mojave | 1982 |
| Schneider's Bakery | television production company | Los Angeles | June 6, 1996 |
| Scholastic Corporation | media distributor, book publisher, business, education company, public company | New York City, Scholastic Building | 1920 |
| Schomburg Center for Research in Black Culture | library branch, creative residency, research library, public library, library building | — | 1925 |
| School of Visual Arts | private for-profit educational institution, art academy, university | New York City | 1947 |
| Schweizer Aircraft Corporation | former entity, organization, business | Horseheads, New York City | 1939 |
| Scribd | online service, organization, business | San Francisco | March 2006 |
| Scripps Institution of Oceanography | centre for marine biology, educational institution, research institute | — | 1903 |
| SDI Media Group | film organization, business | Culver City | 1965 |
| Seabourn Cruise Line | business, cruise line | Seattle, Miami | 1986 |
| Seagate Technology | business, enterprise, public company | Cupertino | 1979 |
| Sean Cody | pornography website, pornographic film studio | United States | 2001 |
| Searchlight Pictures | television production company, film production company, film studio, subsidiary company | Los Angeles | 1994 |
| Sears | business, public company | Hoffman Estates | 1892 |
| Seattle Computer Products | business | Seattle | 1979 |
| Seattle University | private not-for-profit educational institution, Catholic university | Seattle | 1891 |
| Seeburg Corporation | business | Chicago | 1902 |
| Sekai Project | video game publisher, business | Norwalk, Los Angeles | 2007 |
| Selznick International Pictures | film production company, film studio | Los Angeles | 1935 |
| Servant Air | airline | Kodiak | 2003 |
| Sesame Workshop | production company, nonprofit organization | 1 Lincoln Plaza, New York City | May 20, 1968 |
| Shaba Games | business | San Francisco | 1997 |
| Shimmer Women Athletes | business, enterprise | Illinois, Chicago, Berwyn | November 6, 2005 |
| Shiny Entertainment | video game developer, business | Laguna Beach, Newport Beach | 1993 |
| Showtime | production company, film production company, cable channel, specialty channel, subscription television | New York City | July 1, 1976 |
| Shrine Auditorium and Expo Hall | auditorium, function hall, theatre building, movie theater | — | 1925 |
| Shure | business, enterprise | Niles | 1925 |
| Shutterstock | business, enterprise, public company | New York City, Empire State Building | 2003 |
| Sierra Nevada Brewing Company | brewery | Chico | 1980 |
| Sierra Nevada Corporation | business | Sparks | 1963 |
| Signetics | integrated device manufacturer | Sunnyvale | 1961 |
| Silver Lake | business, enterprise | Menlo Park | 1999 |
| Silvergate Capital | savings and loan association, bank, business, public company | La Jolla | 1988 |
| Simon & Schuster | book publisher, publishing house | New York City | 1924 |
| Sinclair Broadcast Group | business, enterprise, public company | Hunt Valley, Cockeysville, Union Valley | 1971 |
| Sinclair Oil Corporation | business, gas station chain | Salt Lake City | May 1, 1916 |
| Six Flags Great Adventure | animal theme park | — | July 1, 1974 |
| Six Flags Over Georgia | theme park | — | 1967 |
| Sizzler | restaurant chain | Mission Viejo | January 27, 1958 |
| Skadden, Arps, Slate, Meagher & Flom | law firm | 1 Manhattan West | 1948 |
| Skybound Entertainment | business | Beverly Hills | 1992 |
| Skydance Animation | animation studio | Santa Monica | March 16, 2017 |
| Skydance Direct-to-Consumer | media company | San Francisco | April 12, 2007 |
| Skydance Media | production company, business | Hollywood | 2006 |
| Skywalker Sound | business, recording studio | Lucas Valley | 1975 |
| SkyWest Airlines | regional airline | St. George | 1972 |
| SLB | business, enterprise, public company, oilfield service company | Houston | 1926 |
| Sledgehammer Games | video game developer | Foster City | 2009 |
| Snap-on | business, public company | Kenosha | 1920 |
| Society of Biblical Literature | organization, open-access publisher, scientific society, learned society | Atlanta | 1880 |
| Soka University of America | private not-for-profit educational institution, higher education institution, school | Aliso Viejo | 2001 |
| Sonos | business, enterprise, public company | Santa Barbara | 2002 |
| Sony Pictures Classics | film production company, film distributor | New York City, Los Angeles | January 1992 |
| Sony Pictures Motion Picture Group | business | Culver City | 1998 |
| SoundHound | music recognition software, enterprise, public company | Santa Clara | September 2005 |
| Southeastern Louisiana University | public educational institution of the United States, university | — | 1925 |
| Southern Company | energy company, business, enterprise, public company | Atlanta | 1945 |
| Southern Illinois University | state university system | — | 1869 |
| Southwestern University | liberal arts college, Colleges That Change Lives, private not-for-profit educational institution | — | 1840 |
| SpaceX | launch service provider, business, public company, aerospace manufacturer | Starbase | March 14, 2002 |
| Spalding | sporting goods manufacturer | Bowling Green | 1876 |
| Specialized Bicycle Components | bicycle manufacturer, business, enterprise | Morgan Hill | 1974 |
| Spectrum Brands | business, enterprise, public company | Middleton | 1906 |
| Sports Reference | business | Philadelphia | December 3, 2007 |
| Springfield Armory | business | Geneseo | 1974 |
| Springfield College | private not-for-profit educational institution | Springfield | 1885 |
| Sprint Corporation | mobile network operator, business, enterprise, public company | Overland Park | 1899 |
| Squarespace | commercial organization, public company | New York City | 2003 |
| SRAM Corporation | bicycle part manufacturing company | Chicago | 1987 |
| SSC North America | business, enterprise, automobile manufacturer | West Richland | 1999 |
| St. Ambrose University | private not-for-profit educational institution, seminary, university, building | — | 1882 |
| St. Cloud State University | public educational institution of the United States, university | St. Cloud | 1869 |
| St. Lawrence University | private not-for-profit educational institution, liberal arts college in the United States, private university | Canton | 1856 |
| Standard Oil of Ohio | business, gas station chain | Cleveland | 1911 |
| Stanford Graduate School of Business | business school, graduate school, organization | — | 1925 |
| Stanley Black & Decker | business, public company | New Britain | 1843 |
| Stanley Motor Carriage Company | automobile manufacturer | Newton | 1902 |
| Staples Inc. | business, retail chain, enterprise, public company | Framingham | 1986 |
| Starbucks | café chain | Seattle | March 30, 1971 |
| Stardust Resort and Casino | skyscraper, casino, hotel, music venue | — | 1958 |
| Starkey Hearing Technologies | business | Eden Prairie | 1967 |
| Starwood | business, enterprise, public company | White Plains | 1930 |
| State Farm Insurance | business, car insurance company, life insurance company, property insurance company | Bloomington | 1922 |
| State Street Corporation | global systemically important bank, business, enterprise, credit institution, public company | Boston | 1792 |
| State University of New York at Purchase | public educational institution of the United States, university | — | 1967 |
| Steak 'n Shake | restaurant chain, business, enterprise | Indianapolis | 1934 |
| Steelcase | business, public company | Grand Rapids | 1912 |
| Stepan Company | business, public company | Northfield | 1932 |
| Sterling Memorial Library | academic library, library building | — | 1930 |
| Sterling Trucks | truck manufacturer, commercial vehicle manufacturer | Redford | 1997 |
| Stetson University | private not-for-profit educational institution, university | DeLand | 1883 |
| Steve Jackson Games | tabletop role-playing game publisher, board game publishing company | Austin | 1980 |
| Stockton University | public educational institution of the United States, university | — | 1969 |
| Stony Brook University | research university, public educational institution of the United States, public university | Stony Brook University | September 16, 1957 |
| Strand Bookstore | book vendor | — | 1927 |
| Strategic Simulations | video game publisher, video game developer, business, enterprise | Sunnyvale | 1979 |
| Strategy | software company, business, public company | Tysons | 1989 |
| Stratolaunch Systems | business, enterprise | Montgomery, Seattle | 2011 |
| Stripe | payment processor, business | San Francisco, South San Francisco | 2010 |
| Stüssy, Inc. | business, enterprise | Irvine | 1980 |
| Substack | website, publishing platform, business, podcast hosting service, enterprise, service | — | November 29, 2017 |
| Sucker Punch Productions | video game developer | Bellevue | October 1997 |
| Sullivan & Cromwell | law firm | New York City | 1879 |
| Sun Microsystems | software company, academic spin-off, business, public company | Santa Clara | February 24, 1982 |
| Sunkist Growers | business, enterprise | Los Angeles | August 29, 1893 |
| Sunoco | oil company, business, gas station chain, enterprise | Dallas | 1886 |
| Supergiant Games | video game publisher, video game developer | San Jose | 2009 |
| SurveyMonkey | customer experience management, software as a service, service on Internet, trademark, enterprise feedback management, online survey service, market research and public opinion polling, business, Customer experience systems, public company, market research | San Mateo | 1999 |
| Swarthmore College | liberal arts college, private not-for-profit educational institution | — | 1864 |
| Swift Engineering | business, enterprise, aerospace manufacturer | San Clemente | 1983 |
| Symbolics | business | Concord | 1979 |
| Synaptics | technology company, business, enterprise | Santa Clara | 1986 |
| Synopsys | business, enterprise, public company | Mountain View | 1986 |
| Sysco | business, public company | Houston | 1969 |