| Soft Pauer Global Limited | Information & communication | 2014 |
| Softontrent Ltd | Information & communication | 2025 |
| Softpress Ltd | Information & communication | 2015 |
| Solartek Services Limited | Construction | 2026 |
| Someguy Prints Ltd | Manufacturing | 2023 |
| Somerville Solutions Limited | Professional & scientific | 2013 |
| Somewhere on the Meadow Limited | Hospitality | 2023 |
| Sophie's Salon Ltd | Other services | 2021 |
| Sorted Media Productions Limited | Information & communication | 2011 |
| Sound-Link Proaudio Limited | Wholesale & retail | 2012 |
| South Central Fleet Services Limited | Wholesale & retail | 2015 |
| South Oxford Investment Ltd | Real estate | 2025 |
| South Willow Developments Limited | Real estate | 2013 |
| Southfield Livestock Limited | Agriculture & fishing | 2021 |
| Sovereign Builders Limited | Construction | 2008 |
| Sovereign Investment Group Limited | Professional & scientific | 2009 |
| Sovereignty Consulting Ltd | Other services | 2026 |
| SP Ventilation Ltd | Extraterritorial | 2019 |
| Spa Performance Limited | Professional & scientific | 2001 |
| Spac Pneumatic Ltd | Manufacturing | 2024 |
| Space Bicester CIC | Education | 2025 |
| Space Biological Sciences Ltd. | Professional & scientific | 2019 |
| Spark Media Limited | Manufacturing | 2022 |
| Spark Supply Chains Advisory Limited | Professional & scientific | 2018 |
| Sparkline Solutions Ltd | Administrative & support | 2025 |
| Sparta Civil Engineering Limited | Construction | 2014 |
| Spartacus Group Limited | Financial services | 2017 |
| Spatial Vantage Ltd | Extraterritorial | 2026 |
| Spax Performance Limited | Manufacturing | 1999 |
| SPD Refurbishment Services Ltd | Construction | 2021 |
| SPD Renovation Services Ltd | Construction | 2024 |
| Spearca Ltd | Administrative & support | 2024 |
| Spectre Stack Ltd | Information & communication | 2025 |
| Spectrum Group International Limited | Professional & scientific | 2005 |
| Speedequipe Motorsport Limited | Extraterritorial | 2002 |
| Speedysisters Ltd | Administrative & support | 2022 |
| Spfc Transports Ltd | Transport & logistics | 2021 |
| Spice Bite Cuisine Ltd | Wholesale & retail | 2020 |
| Spinesirgery Limited | Information & communication | 2016 |
| Spires Plumbing & Heating Oxford Ltd | Construction | 2025 |
| Splurge Shoppers Limited | Wholesale & retail | 2022 |
| SPORT3 Limited | Wholesale & retail | 2020 |
| Sporting Experience Racing Futures CIC | Arts & recreation | 2026 |
| Spot Consultancy Limited | Health & social care | 2013 |
| Sprintslide Limited | Hospitality | 2026 |
| Spud Junction Ltd | Hospitality | 2025 |
| Squarefootage Investment Limited | Real estate | 2020 |
| Squarepaint Ltd | Wholesale & retail | 2023 |
| Squeakycleen Ltd | Administrative & support | 2025 |
| Srav-Sai Consulting Ltd | Information & communication | 2018 |
| SRH Professional Safeguarding Services Ltd | Professional & scientific | 2022 |
| SRI Development Corp Ltd | Information & communication | 2019 |
| SRL Business Development Ltd | Professional & scientific | 2023 |
| Srynix Ltd | Information & communication | 2025 |
| SS Autotech Ltd | Manufacturing | 2022 |
| SS Logistics & Quality Ltd | Transport & logistics | 2019 |
| Ssdev Ltd | Other services | 2012 |
| SSG Global Limited | Health & social care | 2011 |
| SSW Associates (UK) Ltd | Professional & scientific | 2015 |
| SSW Automotive Limited | Professional & scientific | 2019 |
| ST Agnes Bakery Ltd | Manufacturing | 2017 |
| ST Anthony Repatriation Ltd | Arts & recreation | 2009 |
| ST Business Consultancy Ltd | Professional & scientific | 2025 |
| ST Engineering Aerospace Composites Ltd | Professional & scientific | 2026 |
| ST Engineering Aerospace Rotables Limited | Other services | 1990 |
| ST Engineering Antycip Ltd | Administrative & support | 2006 |
| ST Engineering RHQ Ltd. | Administrative & support | 1989 |
| ST George Building Material Ltd | Wholesale & retail | 2025 |
| Staaff Limited | Information & communication | 2020 |
| Stable Stop Ltd | Information & communication | 2026 |
| Stack & Jones Limited | Professional & scientific | 2014 |
| Stacy's Beauty and Hair Extensions Limited | Other services | 2018 |
| Stag Building and Letting Ltd | Wholesale & retail | 2009 |
| Stage Interiors Limited | Professional & scientific | 2019 |
| Stand Tall Amongst Giants Clothing Ltd. | Wholesale & retail | 2012 |
| Stanture Limited | Information & communication | 2012 |
| Stapley Property Limited | Real estate | 2018 |
| Star 69 Film Burst Bubble Limited | Information & communication | 2023 |
| Star HAO Cleaning Service Limited | Administrative & support | 2026 |
| Star Rise Investments Ltd | Real estate | 2024 |
| Starburst Data UK Limited | Information & communication | 2020 |
| Stark Engineering Limited | Professional & scientific | 2017 |
| Starlight Creative Limited | Arts & recreation | 2018 |
| Starquake Limited | Information & communication | 2010 |
| Startermotor Limited | Wholesale & retail | 2016 |
| Statera Medical Ltd | Health & social care | 2026 |
| Station Yard Management Company Limited | Real estate | 2009 |
| Steadfast Solicitors Limited | Professional & scientific | 2015 |
| Steerclear Ltd | Information & communication | 2025 |
| Steeva Care Ltd | Health & social care | 2015 |
| Stefan Motors Ltd | Manufacturing | 2019 |
| Sterling Valor Ltd | Financial services | 2025 |
| Steve Adcock Limited | Construction | 2013 |
| Steve Pitcher Limited | Construction | 2005 |
| Steveknightsurvey Limited | Professional & scientific | 2024 |
| Stevens Landscape Management Ltd | Administrative & support | 2023 |
| Sticki Limited | Construction | 2011 |
| Sticktogether Limited | Professional & scientific | 2004 |
| Stone Barn Media Limited | Information & communication | 2010 |
| Storage Made Easy Limited | Extraterritorial | 2012 |