| Shelf.NetworkFintech | Fintech | Berlin, Germany | — | shelf.network |
| ShieldpayFintech | Fintech | London, United Kingdom | Tom Clementson | shieldpay.com |
| ShiperiseFintech | Fintech | Brussels, Belgium | — | shiperise.com |
| ShippableOther | Other | Bellevue, United States | Avi Cavale | shippable.com |
| Shipshape Urban FarmsIndustrials | Industrials | Mobile, United States | — | shipshapeurbanfarms.com |
| ShofoB2B | B2B | — | | shofo.ai |
| SholderHealthcare | Healthcare | Boulder, United States | — | sholder.com |
| ShookB2B | B2B | Tzur Hadassah, Israel | — | shoook.io |
| Shop LatinxOther | Other | Los Angeles, United States | — | shoplatinx.com |
| ShoppermotionOther | Other | San Francisco, United States | Sergi Palau | shoppermotion.com |
| ShopventoryFintech | Fintech | San Diego, United States | Brandon Billinger | shopventory.com |
| ShorFintech | Fintech | San Francisco, United States | Daivik Goel | tryshor.com |
| ShortwaveB2B | B2B | United States | Andrew Lee | shortwave.com |
| ShurpaIndustrials | Industrials | Chicago, United States | — | shurpa.com |
| SidekickFintech | Fintech | — | Brian Acton | sidekickmoney.com |
| SideTourOther | Other | New York City, United States | Vipin Porwal | sidetour.com |
| Sidewalk InsuranceOther | Other | New York City, United States | — | sidewalk.biz |
| SIEMonsterB2B | B2B | New York City, United States | — | siemonster.com |
| Sigma RatingsOther | Other | New York City, United States | Stuart Jones | sigmaratings.com |
| SigmanticAIB2B | B2B | Dublin, United States | | sigmanticai.com |
| SignalOther | Other | Novi, United States | — | signal.co |
| SignalOpsB2B | B2B | Jamaica, United States | — | cadena.dev |
| SikoiaFintech | Fintech | — | Alexis Rog | sikoia.com |
| SilaB2B | B2B | — | | silahq.com |
| Silene BiotechHealthcare | Healthcare | Seattle, United States | — | silenebiotech.com |
| SilversheetOther | Other | Culver City, United States | Daniel Kivatinos | silversheet.com |
| SimbaPayFintech | Fintech | London, United Kingdom | Edriss Tukurah | simbapay.com |
| SimBull Sports ExchangeFintech | Fintech | Minneapolis, United States | Jake Buse | simbull.com |
| SimicXB2B | B2B | Brentford, United Kingdom | — | simicx.com |
| Simple EnergyIndustrials | Industrials | Boulder, United States | Suhas Rajkumar | simpleenergy.com |
| SimpleTaxFintech | Fintech | — | Jonathan Suter | gosimpletax.com |
| SimplifyberIndustrials | Industrials | New York City, United States | Maria Intscher-Laskowski | simplifyber.com |
| SimplyMeetConsumer | Consumer | Wilmington, United States | — | beeinvites.com |
| SimrekaB2B | B2B | Utrecht, Netherlands | — | simreka.com |
| SimudyneB2B | B2B | London, United Kingdom | Justin Lyon | simudyne.com |
| SinaiIndustrials | Industrials | United States | Kirsten Temme | sinaitechnologies.com |
| SingulateB2B | B2B | — | — | singulate.com |
| SIQ BasketballOther | Other | Charlotte, United States | — | siqbasketball.com |
| SiraB2B | B2B | — | | sira.team |
| SiriusOther | Other | Amsterdam, Netherlands | — | besirius.io |
| SitterConsumer | Consumer | Boulder, United States | — | sitter.me |
| SkenarioLabsFintech | Fintech | Espoo, Finland | Juho Seppänen | skenariolabs.com |
| SketchfabB2B | B2B | New York City, United States | Alban Denoyel | sketchfab.com |
| SkewFintech | Fintech | — | Stéphane Ouellette | skew.com |
| SkillPopEducation | Education | Charlotte, United States | Haley Bohon | skillpop.com |
| SkillsyncB2B | B2B | — | Narayana Aaditya Ganeshkumar | skillsync.wiki |
| Skintelligent CorporationOther | Other | Atlanta, United States | — | skintelligentlab.com |
| SkiptownOther | Other | Charlotte, United States | — | skiptown.io |
| SkopeB2B | B2B | San Francisco, United States | | useskope.com |
| SkopenowOther | Other | New York City, United States | Jonathan Vitelli | skopenow.com |