| Simplex Tax Limited | Professional & scientific | 2023 |
| Simply Collect Ltd | Information & communication | 2014 |
| Simply Trade Limited | Wholesale & retail | 2025 |
| Sincera Ltd | Information & communication | 2023 |
| Singh Care Limited | Health & social care | 2020 |
| Sinith Property Development Ltd | Real estate | 2019 |
| Sinith Travel Ltd | Administrative & support | 2024 |
| Sisters in Blossom Ltd | Education | 2025 |
| Sitioweb Ltd | Information & communication | 2019 |
| Sitwise Ltd | Transport & logistics | 2025 |
| SIX Lines Ltd | Information & communication | 2014 |
| Sixth Gear Services Ltd | Transport & logistics | 2018 |
| Siyamate Limited | Health & social care | 2013 |
| Sizeroy Limited | Wholesale & retail | 1984 |
| SJ Brierley Investments Ltd | Financial services | 2025 |
| SJ Electrics and Fire Limited | Construction | 2025 |
| SJS Realty Limited | Real estate | 2024 |
| SK Estates Ltd | Real estate | 2012 |
| SK Local Store Ltd | Wholesale & retail | 2023 |
| SK Travel.Club Ltd | Administrative & support | 2022 |
| SK Waste Management Limited | Professional & scientific | 2019 |
| Skannive Utilities Limited | Construction | 2018 |
| SKB Courier Logistic Ltd | Transport & logistics | 2023 |
| SKI Carriage Limited | Transport & logistics | 2009 |
| SKI Helicopters Limited | Professional & scientific | 2016 |
| SKI Miles Limited | Administrative & support | 2009 |
| Skinner Farmers Limited | Agriculture & fishing | 2026 |
| Skol Knives UK Ltd | Manufacturing | 2025 |
| Sky High Allstars CIC | Arts & recreation | 2025 |
| Sky View Bedford Ltd | Real estate | 2018 |
| Skyclad Ltd | Professional & scientific | 2025 |
| Skyfall Properties Northampton Ltd | Other services | 2015 |
| Skyhouse Investment Ltd | Real estate | 2022 |
| Skyline Lofts Ltd | Construction | 2022 |
| Skyline Property Sourcing Ltd | Real estate | 2024 |
| Skyllian Consultancy Ltd | Professional & scientific | 2015 |
| Skymaple Ltd | Public administration | 2021 |
| Skysun Solutions Ltd | Real estate | 2024 |
| Skytech Helicopters Limited | Professional & scientific | 2003 |
| Skywalker One Ltd | Transport & logistics | 2015 |
| Skyward Circle Ltd | Transport & logistics | 2025 |
| Skywood Joinery Limited | Construction | 2014 |
| SL Commercials Ltd | Wholesale & retail | 2015 |
| Slatrex UK Ltd | Manufacturing | 2024 |
| Slawo Trans Ltd | Transport & logistics | 2018 |
| Slawomir Sitko Ltd | Transport & logistics | 2017 |
| SLB ACP Limited | Health & social care | 2024 |
| SLG Lift Solutions Ltd | Manufacturing | 2024 |
| Sliwka Limited | Transport & logistics | 2016 |
| Sljw Communications Limited | Information & communication | 2022 |
| SLM Brickwork Limited | Construction | 2020 |
| Slug Communications Ltd | Professional & scientific | 2023 |
| SM K9-SECURITY Ltd | Administrative & support | 2021 |
| Smallteeth DOC Limited | Health & social care | 2023 |
| Smart English Classes Ltd | Education | 2018 |
| Smart Labels UK (PVT) Ltd | Manufacturing | 2022 |
| Smart Network Solutions Ltd | Information & communication | 2020 |
| Smart Rescue and Logistics Ltd | Wholesale & retail | 2025 |
| Smart Shine Carwash Ltd | Other services | 2017 |
| Smarta Move Limited | Real estate | 2018 |
| Smartamove Holding Limited | Financial services | 2020 |
| Smarter Servicing Ltd | Manufacturing | 2025 |
| Smash N Smoke Ltd | Hospitality | 2026 |
| SMB Spedition Ltd | Transport & logistics | 2020 |
| Smdt Consultancy Limited | Professional & scientific | 2016 |
| Smilax WB Ltd | Wholesale & retail | 2011 |
| Smile Revolution Growth Hub CIC | Education | 2021 |
| Smile Revolution Limited | Professional & scientific | 2016 |
| Smile Vinil CUT Ltd | Wholesale & retail | 2025 |
| Smiles on Faces Limited | Health & social care | 2019 |
| Smiley Homes Limited | Real estate | 2020 |
| Smith and Edwards Limited | Wholesale & retail | 2022 |
| Smith Cleaning Services Northampton Limited | Administrative & support | 2023 |
| Smithhillman Ltd | Health & social care | 2018 |
| Smits Management Ltd | Real estate | 2015 |
| SMM Transport Ltd | Transport & logistics | 2019 |
| Smooth Transitions Ltd | Extraterritorial | 2020 |
| SMP Spedition Ltd | Transport & logistics | 2023 |
| Smtd Property Ltd | Real estate | 2026 |
| SNB & JCB Holdings Limited | Financial services | 2025 |
| SND Construction Ltd | Construction | 2026 |
| SND Courier Ltd | Transport & logistics | 2022 |
| Snowdrops Recruitment Limited | Administrative & support | 2026 |
| Sodhapop Limited | Professional & scientific | 2015 |
| Sofamall Ltd | Wholesale & retail | 2022 |
| SOL Paraiso Limited | Professional & scientific | 2019 |
| Solar Pubs Limited | Hospitality | 2026 |
| Solid Wise Solution Ltd | Construction | 2022 |
| Solo Accountant Ltd | Professional & scientific | 2013 |
| Solo Accountant Plus Ltd | Professional & scientific | 2014 |
| Solo Property Development Ltd | Real estate | 2017 |
| Solo Property Plus Ltd | Real estate | 2020 |
| Soma Lives Limited | Wholesale & retail | 2025 |
| Somnium Projects Ltd | Financial services | 2019 |
| Sonas Textile Limited | Water & waste | 2007 |
| Sonder Experiential Ltd | Professional & scientific | 2024 |
| Sons Local Limited | Wholesale & retail | 2024 |
| Sons Mentors Ltd | Education | 2026 |
| Soricas Properties Ltd | Real estate | 2023 |
| Sorin Danila Ltd | Transport & logistics | 2015 |