| SubmitShop | New York |
| Submittable | |
| Subnation | California |
| Subnet Zero | Washington |
| SubPLY | California |
| Subscript.com | California |
| Subsense | California |
| SubShort, Inc. | |
| Subsidium, Inc. | Virginia |
| Subsite Electronics | Oklahoma |
| Subspace Labs, Inc. | California |
| Subsplash | Texas |
| Substack, Inc. | |
| Substrate Labs, Inc. | |
| SubSummit | |
| Subterra AI, Inc. | Ohio |
| Subtle | |
| Subtle Medical, Inc. | California |
| Suburban Chicago Apple Users | Illinois |
| Suburban Computer Services, Inc. | Michigan |
| Suburban Imaging | Minnesota |
| Suburban Machinery Software, Inc. | Ohio |
| Suburban Software Systems, Inc. | Alabama |
| Succeed.net | California |
| Success City Online | |
| Success Link Outsourcing | |
| Success Makers | California |
| Success Systems | Connecticut |
| Success Venture Partners | |
| SuccessED | Texas |
| Successeve, Inc. | Massachusetts |
| Successware SPE, LLC | |
| Succinct | |
| SucessAmp, LLC | Michigan |
| Sucker Punch Productions, LLC | Washington |
| Sucuri Security | California |
| Sudancer Solutions, LLC | |
| Sudo Biosciences, Inc. | Indiana |
| Sudo Biosciences, Inc. | |
| Sudo Solutions | |
| SUDO, LLC | |
| Sudolabs | |
| Suffescom Solutions, Inc. | |
| Suffescom Solutions, Inc. | |
| Suffolk County Webmasters | |
| Suffolk Technologies | Massachusetts |
| Suffolk University | Massachusetts |
| SugarCRM, Inc. | California |
| Sugarloaf Network Systems | Maryland |
| SugarSync | New York |