| SteadOther | Other | Reigate, United Kingdom | — | joinstead.com |
| Stellon LabsB2B | B2B | San Francisco, United States | | stellonlabs.com |
| Stemma AIB2B | B2B | London, United Kingdom | Etai Lahav | stemma-ai.com |
| StepLadderFintech | Fintech | — | Richard Dana | joinstepladder.com |
| STHRIVEOther | Other | Dubai, United Arab Emirates | — | sthrive.com |
| StiltaB2B | B2B | — | | stilta.com |
| StocklineB2B | B2B | San Francisco, United States | | stockline.ai |
| StocklyOther | Other | Vitry-sur-Seine, France | Adrien Berthou | stockly.ai |
| StopLightB2B | B2B | Austin, United States | Marc MacLeod | stoplight.io |
| StoreCashFintech | Fintech | San Jose, United States | — | storecashapp.com |
| StoretaskerHealthcare | Healthcare | New York City, United States | — | storetasker.com |
| Storey The AppConsumer | Consumer | San Francisco, United States | — | storeytheapp.com |
| StormSensorIndustrials | Industrials | Seattle, United States | Erin Rothman | stormsensor.io |
| StoryTapOther | Other | Port Coquitlam, Canada | Margot Leong | storytap.com |
| StorywiseB2B | B2B | Ra'anana, Israel | Yoav Vilner | storywise.ai |
| StotlesB2B | B2B | — | Tom Brinded | stotles.com |
| str8batConsumer | Consumer | Bengaluru, India | Soham Sheth | str8bat.com |
| Strand AIHealthcare | Healthcare | — | Yue Dai | strandai.com |
| StreadyOther | Other | Trondheim, Norway | — | stready.com |
| StreamB2B | B2B | Boulder, United States | Thierry Schellenbach | getstream.io |
| StreambasedB2B | B2B | — | — | streambased.io |
| StreamrootB2B | B2B | New York City, United States | Victorian Basta | streamroot.io |
| StreetMetricsConsumer | Consumer | Birmingham, United States | Maurice Riley | streetmetrics.com |
| StripeFintech | Fintech | — | Patrick Collison | stripe.com |
| StrobeB2B | B2B | Providence, United States | — | strobelabs.com |
| Structured AIOther | Other | New York, United States | Raymond Zhao | getstructured.ai |
| StrydOther | Other | Boulder, United States | Angus Nelson | stryd.com |
| StudentFinanceFintech | Fintech | — | Mariano Kostelec | studentfinance.com |
| stupeflixConsumer | Consumer | — | Nicolas Garret | stupeflix.com |
| StyleSageB2B | B2B | New York City, United States | Elizabeth Shobert | stylesage.co |
| SuccessionMatchingB2B | B2B | Moose Jaw, Canada | — | successionmatching.com |
| SuggesticOther | Other | Palo Alto, United States | Victor Chapela | suggestic.com |
| SumlyFintech | Fintech | New York City, United States | — | getsumly.com |
| SunairioOther | Other | Baltimore, United States | — | sunairio.com |
| SunflowerConsumer | Consumer | — | | sunflowersober.com |
| SunlightB2B | B2B | — | — | sunlight.is |
| Sunlight TechnologiesEducation | Education | San Francisco, United States | — | sunlight.is |
| SunriseB2B | B2B | — | — | sunriserobotics.co |
| SuntheticsB2B | B2B | New York City, United States | Daniela Blanco | sunthetics.io |
| Super DispatchFintech | Fintech | Kansas City, United States | Askar Bulegenov | mysuperdispatch.com |
| SupercedeFintech | Fintech | — | Jerad Leigh | supercede.com |
| Superfan StudioB2B | B2B | Dallas, United States | — | superfan.studio |
| SuperpoweredOther | Other | Austin, United States | Dan Kantor | superpowered.com |
| SuperQuickQuestionOther | Other | Astoria, United States | — | superquickquestion.com |
| superscriptFintech | Fintech | — | Cameron Shearer | gosuperscript.com |
| SupersetB2B | B2B | — | | superset.sh |
| SureformB2B | B2B | Palo Alto, United States | | sureformhq.com |
| SurfboardB2B | B2B | — | Melanie Fellay | teamsurfboard.com |
| SurfLabOther | Other | Currumbin Waters, Australia | — | surflab.ai |
| Surge AfricaFintech | Fintech | Wilmington, United States | — | surgeafrica.co |