| Simply360 | |
| SimplyReliable | Massachusetts |
| SimplyRETS | |
| Simpod, Inc. | California |
| Simporter, Inc. | Arkansas |
| Simpson College | Iowa |
| Simpson Interventions, Inc. | |
| Simpson Research Company, Inc. | Vermont |
| Simpson University | California |
| Simrex Corporation | New York |
| SIMS Software | California |
| SIMS, Inc. | California |
| Simspace | |
| Simspace Corporation | Massachusetts |
| SimSplit | Delaware |
| SimSTAFF Technical Services | Florida |
| Simtech Development | California |
| Simtek, Inc. | Texas |
| Simtra BioPharma Solutions | |
| Simublade | |
| Simul8 Corporation | Massachusetts |
| Simulation Interoperability Standards Organization | |
| Simulation Technologies, Inc. | Alabama |
| Simulation Theory, Inc. | |
| Simulations Plus, Inc. | California |
| Simulmedia, Inc. | New York |
| Simultaneous Solutions, Inc. | Florida |
| SimuQuest | Michigan |
| SimVentions, Inc. | Virginia |
| SIMX Corporation | New Jersey |
| Sin City Computer Services, LLC | Nevada |
| SINAI Technologies | California |
| Sinatra | Arizona |
| Sinca | Texas |
| Sincerely | California |
| Sinclair College | Ohio |
| Sinclair Manufacturing Company | Pennsylvania |
| Sindri Technologies, Inc. | |
| SindyXR, Inc. | |
| Sine Wave Solutions, LLC | California |
| Sinelogix Technologies | |
| SineWave Technologies | Indiana |
| SineWave Ventures | Virginia |
| Singer Electronics | Oregon |
| Singh Biotechnology, LLC | Florida |
| Single Cell Technology | California |
| Single Origin Media, LLC | |
| Single Pass, Inc. | |
| Single Point of Contact | California |
| Single Point Solutions | |