| Sendsibl Ltd | Education | 2026 |
| Senna Consult Limited | Professional & scientific | 2017 |
| Senrap Ltd. | Administrative & support | 2001 |
| Sequel UK Limited | Information & communication | 1986 |
| Seronova Limited | Professional & scientific | 2026 |
| Sevensands Locums Limited | Wholesale & retail | 2017 |
| SFR Properties Limited | Real estate | 2017 |
| SG Recovery MK Ltd | Transport & logistics | 2026 |
| SGH Maintenance Limited | Construction | 2011 |
| Shades Decor Ltd | Construction | 2019 |
| Shaggy Dog AI Ltd | Information & communication | 2025 |
| Shaping Recruitment Ltd | Professional & scientific | 2024 |
| Sharespace Ltd | Information & communication | 2018 |
| Shaun Aris Homes Ltd | Construction | 2014 |
| Shelby Nola Limited | Other services | 2022 |
| Shepherd & Co Holdings Limited | Real estate | 2020 |
| Shepherd & Co Solicitors Limited | Professional & scientific | 2019 |
| Sherwill Forbes (Holdings) Limited | Financial services | 2023 |
| Sherwill Forbes (RCD) Limited | Real estate | 2023 |
| Sherwill Forbes Limited | Real estate | 2013 |
| Shiel Projects Ltd | Construction | 2021 |
| Shifterz-Towcester Ltd. | Arts & recreation | 2000 |
| Shire Group Ltd | Professional & scientific | 2020 |
| Shire Property & Asset Investments Ltd | Real estate | 2022 |
| Shore Abode Limited | Hospitality | 2018 |
| Shore Abode Management Limited | Real estate | 2020 |
| Shore Legacy Limited | Real estate | 2018 |
| Si-Cgi Ltd | Arts & recreation | 2011 |
| Sigil Safety Solutions Ltd | Public administration | 2025 |
| Signature 4K Coatings Ltd | Wholesale & retail | 2024 |
| Silent Ember Interactive Limited | Information & communication | 2026 |
| Sillaro Limited | Real estate | 2014 |
| Silson IT Services Limited | Information & communication | 2019 |
| Silson Properties Limited | Construction | 2002 |
| Silva Capital Limited | Financial services | 2017 |
| Silver Rocks Consulting Limited | Professional & scientific | 2019 |
| Silver Sixpence Bridal LLP | | 2015 |
| Silver Stone Search & Selection Ltd | Administrative & support | 2004 |
| Silverstone Accommodation Limited | Construction | 2017 |
| Silverstone Advisory Services Limited | Professional & scientific | 1991 |
| Silverstone Audio Limited | Wholesale & retail | 2003 |
| Silverstone Brewery Ltd | Manufacturing | 2019 |
| Silverstone Cerakote Ltd | Manufacturing | 2023 |
| Silverstone Classic and Race Car Storage Limited | Transport & logistics | 2012 |
| Silverstone Club Limited | Extraterritorial | 1972 |
| Silverstone College of Motorsport Limited | Extraterritorial | 2003 |
| Silverstone Design Holdings Limited | Financial services | 2023 |
| Silverstone Design Limited | Manufacturing | 2008 |
| Silverstone Estates Limited | Real estate | 1971 |
| Silverstone Farm Campsite Limited | Hospitality | 2022 |
| Silverstone Garage Limited | Wholesale & retail | 2006 |
| Silverstone Global Limited | Professional & scientific | 2023 |
| Silverstone Grand Prix Limited | Extraterritorial | 1974 |
| Silverstone Kart Club Limited | Arts & recreation | 2015 |
| Silverstone Logistics Management Ltd | Transport & logistics | 2018 |
| Silverstone Non-Metalix Ltd | Manufacturing | 2024 |
| Silverstone Paint Technology Ltd | Wholesale & retail | 2012 |
| Silverstone Passive (Windows & Doors) Ltd | Professional & scientific | 2025 |
| Silverstone Performance Technologies Limited | Professional & scientific | 2023 |
| Silverstone Racing School Limited | Extraterritorial | 1984 |
| Silverstone Repairs Ltd | Manufacturing | 2025 |
| Silverstone Sports Engineering Hub Ltd | Arts & recreation | 2018 |
| Silverstone Technology Cluster Limited | Administrative & support | 2016 |
| Silverstone Vehicle Hire Ltd | Administrative & support | 2023 |
| Silvertec (UK) Limited | Professional & scientific | 2008 |
| Silverwood Instruments Ltd | Manufacturing | 2021 |
| Silwood Consultancy Limited | Professional & scientific | 2018 |
| Silwood Investments Limited | Real estate | 2021 |
| Simplified Accounting Limited | Professional & scientific | 2011 |
| Simply Random Limited | Wholesale & retail | 2024 |
| Simply Solution Limited | Information & communication | 2000 |
| SIR Henry Royce Limited | Arts & recreation | 1993 |
| Sixtysix Consulting Limited | Professional & scientific | 2013 |
| SJD Group Holding Ltd | Financial services | 2025 |
| SJM PUB Co Limited | Hospitality | 2026 |
| SJT Motorcycles Ltd | Wholesale & retail | 2024 |
| SK Construction and Maintenance Ltd | Construction | 2017 |
| SKI Fibre Ltd. | Information & communication | 2012 |
| Skills for YOU Ltd | Education | 2011 |
| Sknfluence Ltd | Other services | 2023 |
| Skoyen Software Ltd | Information & communication | 2024 |
| Skweeze Limited | Information & communication | 2010 |
| Sladden and Barton Ltd | Information & communication | 1998 |
| Sling & Tackle (Milton Keynes) Limited | Manufacturing | 1986 |
| Slinky Prints Limited | Wholesale & retail | 2020 |
| Smallwood Holdings Ltd | Real estate | 2022 |
| Smart Property Software Ltd | Information & communication | 2026 |
| Smarter Leadership Limited | Professional & scientific | 2020 |
| SMG Education Limited | Education | 2014 |
| Smooth Skin Solutions Ltd | Other services | 2022 |
| SMS Fleet Installations Ltd | Wholesale & retail | 2026 |
| Social Room Ltd | Professional & scientific | 2022 |
| Socialsellr Ltd | Administrative & support | 2024 |
| Sofrabec Property Investments Ltd | Real estate | 2020 |
| Sola & F. Enterprises Ltd | Financial services | 2020 |
| Solera Engineering Limited | Professional & scientific | 2024 |
| Solo Precision Ltd | Manufacturing | 2020 |
| Solstice Festival Ltd | Administrative & support | 2025 |
| Solstice P3 Consulting Limited | Professional & scientific | 2015 |
| Solstice Property Investment Limited | Real estate | 2019 |