| SCSfw&d Company, INC. | South San Francisco | CA | Wood Product Manufacturing321911 | — | ◇ UNVERIFIED |
| SBShaw Bakers | South San Francisco | CA | Food Manufacturing311812 | — | ◇ UNVERIFIED |
| STShinobi Therapeutics INC. | South San Francisco | CA | Chemical Manufacturing325414 | — | ◇ UNVERIFIED |
| SESieger Engineering INC | South San Francisco | CA | Machinery Manufacturing333319 | — | ◇ UNVERIFIED |
| STSing Tao Newspaper (sf) LTD | South San Francisco | CA | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| STSiteone Therapeutics | South San Francisco | CA | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
| SLSouthline - Lpgs Tanforan LLC | South San Francisco | CA | Fabricated Metal Product Manufacturing332999 | — | ◇ UNVERIFIED |
| STSpiral Therapeutics INC | South San Francisco | CA | Chemical Manufacturing325411 | — | ◇ UNVERIFIED |
| SASports and Graphics | South San Francisco | CA | Printing and Related Support Activities323113 | — | ◇ UNVERIFIED |
| SPSunesis Pharmaceuticals INC | South San Francisco | CA | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
 Super Color Digital LLC | South San Francisco | CA | Printing and Related Support Activities323111 | — | ◇ UNVERIFIED |
| STSwitch Therapeutics | South San Francisco | CA | Chemical Manufacturing325411 | — | ◇ UNVERIFIED |
| TFThermo Fisher Scientific | South San Francisco | CA | Computer and Electronic Product Manufacturing334516 | — | ◇ UNVERIFIED |
| TTTizona Theraputics INC | South San Francisco | CA | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
| TBTopos Bio INC | South San Francisco | CA | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
| TNTrace Neuroscience | South San Francisco | CA | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
| TETranscoast Envelope Company | South San Francisco | CA | Paper Manufacturing322230 | — | ◇ UNVERIFIED |
| TTTwenty/twenty Therapeutics | South San Francisco | CA | Miscellaneous Manufacturing339113 | — | ◇ UNVERIFIED |
| TBTwist Bioscience | South San Francisco | CA | Chemical Manufacturing325414 | — | ◇ UNVERIFIED |
| UUUngo Ultimate Finishes INC | South San Francisco | CA | Furniture and Related Product Manufacturing337110 | — | ◇ UNVERIFIED |
| UBUnity Biotechnology | South San Francisco | CA | Chemical Manufacturing325412 | — | ◇ UNVERIFIED |
| VIVitrolabs INC | South San Francisco | CA | Chemical Manufacturing325414 | — | ◇ UNVERIFIED |
| WLWatchpoint Logistics, INC. | South San Francisco | CA | Computer and Electronic Product Manufacturing334515 | — | ◇ UNVERIFIED |
| XGX Gen US CO | South San Francisco | CA | Chemical Manufacturing325414 | — | ◇ UNVERIFIED |
 Yenzym Antibodies LLC | South San Francisco | CA | Chemical Manufacturing325414 | — | ◇ UNVERIFIED |
