| Sellhomesearch Ltd | Real estate | 2018 |
| SEN People Ltd | Administrative & support | 2021 |
| Senali Property Management Limited | Real estate | 2025 |
| Senico Surveys & Engineering Limited | Construction | 2025 |
| Serena Homes Limited | Wholesale & retail | 2025 |
| Serene Components Limited | Wholesale & retail | 2025 |
| Serenity Cyber Alliance CIC | Information & communication | 2025 |
| Service Climate Management Ltd | Professional & scientific | 2008 |
| Servygo Ltd | Construction | 2024 |
| Sessionworld Limited | Arts & recreation | 1986 |
| SEVEN21 Design Limited | Professional & scientific | 2010 |
| Sexy Erotica Ltd | Wholesale & retail | 2025 |
| Seymour Catering Ltd | Hospitality | 2016 |
| SG Kaya Ltd | Hospitality | 2022 |
| SGE Driving Services Ltd | Transport & logistics | 2015 |
| SGL Ltd | Construction | 2023 |
| SGS Medical Ltd | Health & social care | 2020 |
| SH Kebab Kingdom Ltd | Hospitality | 2026 |
| Shadowdrive Ltd | Transport & logistics | 2025 |
| Shah and Shah Ltd | Health & social care | 2016 |
| Shai Shammai Consultants Ltd | Professional & scientific | 2021 |
| Shakhera Limited | Health & social care | 2023 |
| Sham Services Ltd | Information & communication | 2025 |
| Shamiana UK Ltd | Hospitality | 2025 |
| Shammah Holdings Ltd | Real estate | 2024 |
| Shanaya Express Limited | Transport & logistics | 2025 |
| Shani Trading Limited | Information & communication | 2022 |
| Shanjeshan Limited | Financial services | 2024 |
| Shaping Excellence CIC | Professional & scientific | 2024 |
| Shara Consultancy Ltd | Professional & scientific | 2023 |
| Shara Solutions Ltd | Information & communication | 2024 |
| Shareen Estates Ltd | Real estate | 2019 |
| Shava Logistics Ltd | Health & social care | 2016 |
| Shava Ltd | Health & social care | 2025 |
| SHE Studio Enterprise Ltd | Arts & recreation | 2023 |
| Shealight Cosmetics Ltd | Manufacturing | 2019 |
| Sheel Health Private Limited | Health & social care | 2023 |
| Sherrards Developments Limited | Construction | 2006 |
| Sherthania Ltd | Health & social care | 2014 |
| Shine Online Marketing Limited | Professional & scientific | 2026 |
| Shiri Enterprise Ltd | Health & social care | 2018 |
| Shivaji Catering Ltd | Hospitality | 2020 |
| Shivram Services Ltd | Information & communication | 2019 |
| Shja Services Limited | Information & communication | 2025 |
| Shmb Consultants Ltd | Professional & scientific | 2010 |
| Shmci Limited | Professional & scientific | 2024 |
| Shoefit.Uk Footwear Ltd | Wholesale & retail | 2021 |
| Shoot Systems Limited | Information & communication | 2008 |
| Shothouse Cant Ltd | Financial services | 2021 |
| Shp-Smart Heat Pumps Imports Limited | Construction | 2024 |
| Shree SAI Consultants UK Ltd | Manufacturing | 2010 |
| Shree Trio Mart Ltd | Wholesale & retail | 2025 |
| Shri Gunatitanand Limited | Wholesale & retail | 2024 |
| Siboz Ltd | Health & social care | 2023 |
| Sidma Events and Entertainment Ltd | Information & communication | 2025 |
| Sigma Programmes Limited | Professional & scientific | 2024 |
| Silas Manhood Photography Limited | Professional & scientific | 2012 |
| Silksense Ltd | Wholesale & retail | 2023 |
| Silony Medical Limited | Manufacturing | 2014 |
| Silvatech Ltd | Information & communication | 2025 |
| Silver Crystal Ltd | Wholesale & retail | 2019 |
| Silver Mountain Data Ltd | Information & communication | 2025 |
| Silver Oak Carers Ltd | Health & social care | 2026 |
| Silver Shamrock Limited | Information & communication | 2020 |
| Silvermont Linings Limited | Professional & scientific | 2024 |
| Silvernoon Limited | Real estate | 2000 |
| Silverstone 55 Limited | Construction | 2023 |
| SIM Signs and Displays Limited | Manufacturing | 2019 |
| SIM1 Racing Ltd | Wholesale & retail | 2016 |
| Simmons (Bakers) Limited | Manufacturing | 1946 |
| Simon Clews Limited | Financial services | 2025 |
| Simon J Tomlinson Limited | Professional & scientific | 2019 |
| Simplified Impact CIC | Education | 2025 |
| Simply Accounts 4U Ltd | Professional & scientific | 2022 |
| Simply Cafe Sandy Ltd | Hospitality | 2026 |
| Simply Food Heaven Ltd | Hospitality | 2018 |
| Simply Inverness Propco Ltd | Real estate | 2023 |
| SIMS4BUSINESS Limited | Wholesale & retail | 2021 |
| SIMS4GROUP Limited | Wholesale & retail | 2019 |
| SIMS4HOME Limited | Wholesale & retail | 2021 |
| SIMS4PURCHASING Limited | Wholesale & retail | 2021 |
| SIMS4STUDENTS Limited | Wholesale & retail | 2021 |
| SIMS4TRAVEL Limited | Wholesale & retail | 2021 |
| Singularity IT Limited | Information & communication | 2014 |
| Sirin Kebab Ltd | Hospitality | 2023 |
| Site Testing Ltd | Professional & scientific | 2015 |
| Siva Enterprises Limited | Hospitality | 2025 |
| SIX Pillars Management Limited | Professional & scientific | 2011 |
| SK Haircare Limited | Other services | 2025 |
| SK Window Cleaning Ltd | Administrative & support | 2025 |
| Skill Hub Limited | Construction | 2025 |
| Skin by DR Caroline Ltd | Health & social care | 2012 |
| Skipper Accounts Limited | Professional & scientific | 2001 |
| Skrawl Limited | Professional & scientific | 2017 |
| Sky Company for Real Estate Investment General Trade and Public Transportation Ltd | Wholesale & retail | 2023 |
| Sky Limit Entertainment Limited | Professional & scientific | 2024 |
| Skylon Construction Limited | Construction | 2015 |
| Skylon Development Limited | Information & communication | 2024 |
| Skylon Easy Doors UK Ltd | Manufacturing | 2023 |
| Skylon Joinery Limited | Manufacturing | 2020 |