| Securox Ltd | Professional & scientific | 2016 |
| SEE This Research Limited | Professional & scientific | 2017 |
| Seedat Gallacher Ltd | Real estate | 2020 |
| Seedat Ltd | Health & social care | 2014 |
| Sekoya Haus Limited | Health & social care | 2025 |
| Sempas Accountants Limited | Professional & scientific | 2018 |
| Sense Away Ltd | Professional & scientific | 2020 |
| Sense Financial Limited | Financial services | 2010 |
| Senso-Ji Sushi Ltd | Wholesale & retail | 2024 |
| Seppi Ltd | Hospitality | 2023 |
| Serafins Design Ltd. | Wholesale & retail | 2018 |
| Serat Security Limited | Administrative & support | 2025 |
| Seren Lewis Enterprises Limited | Administrative & support | 2007 |
| Serendipitea & Coffee Limited | Hospitality | 2012 |
| Serene Path Health Limited | Health & social care | 2025 |
| Serenity Care Homes Ltd | Health & social care | 2012 |
| Serenity Security Limited | Administrative & support | 2016 |
| Sergeant Walnuts Limited | Professional & scientific | 2022 |
| Sero Management Limited | Real estate | 2013 |
| Seth Healthcare Ltd. | Health & social care | 2014 |
| Sevban Agency Ltd | Professional & scientific | 2025 |
| Seven Level Limited | Wholesale & retail | 2013 |
| Seven Level Solutions Limited | Wholesale & retail | 2023 |
| Sevrow Properties Ltd | Real estate | 2022 |
| Sf.Lee Limited | Construction | 2014 |
| Sfinity Services LLC Ltd | Wholesale & retail | 2024 |
| SG Learning Development Solutions Ltd | Professional & scientific | 2017 |
| SG Roofing MCR Limited | Construction | 2026 |
| SG UK International Limited | Manufacturing | 2022 |
| SGG Advisory Ltd | Professional & scientific | 2025 |
| SGR Resource Ltd | Administrative & support | 2013 |
| Shackleford Pianos Limited | Wholesale & retail | 2007 |
| Shades-N-Shelters Ltd | Manufacturing | 2021 |
| Shaft Safety Systems Limited | Professional & scientific | 2023 |
| Shah Business Consultancy Ltd | Professional & scientific | 2014 |
| Shamera Limited | Real estate | 2010 |
| Shanab Barber Shop Limited | Other services | 2020 |
| Shannon Medical Services Ltd | Health & social care | 2021 |
| Sharp Property Platform Assets Ltd | Real estate | 2022 |
| Sharp Property Platform Ltd | Financial services | 2020 |
| Sharples Holdings Limited | Professional & scientific | 2021 |
| Shaw Lifestyle Medicine Limited | Health & social care | 2024 |
| Shawarna Shawarma Limited | Hospitality | 2025 |
| Shawcroft Ltd | Real estate | 2023 |
| SHAWEHOUSE4 Limited | Real estate | 2024 |
| Shea Global Limited | Information & communication | 2003 |
| Shebbi Cloud Tech Ltd | Information & communication | 2025 |
| Sheltered Care Ltd | Health & social care | 2025 |
| Shepherd Welding Solutions Ltd | Construction | 2022 |
| SHG Food Limited | Hospitality | 2021 |
| Shibmed Ltd | Health & social care | 2025 |
| Shieldron Ltd | Wholesale & retail | 2025 |
| Shine MCR Ltd | Wholesale & retail | 2024 |
| Ship Safe Limited | Information & communication | 2025 |
| Shiraz Cottage Limited | Hospitality | 2021 |
| Shires Electrical Services Ltd | Wholesale & retail | 2015 |
| Shiruku Limited | Hospitality | 2024 |
| Shiv Group Limited | Wholesale & retail | 2024 |
| Shooters GIN Company Limited | Manufacturing | 2016 |
| Shopthem Limited | Information & communication | 2001 |
| Short CUT Productions Limited | Information & communication | 2023 |
| SHR Consultancy Services Ltd | Administrative & support | 2025 |
| Shred-It Limited | Administrative & support | 2000 |
| Shree Balaji Private Ltd | Hospitality | 2025 |
| Shriji Global Trade Ltd | Wholesale & retail | 2026 |
| Shrishakti Property Ltd | Real estate | 2025 |
| SHZ Holdings Ltd | Real estate | 2023 |
| SHZ Investments Ltd | Construction | 2022 |
| Siam Noodle Bar Limited | Hospitality | 2025 |
| SID Developers UK Ltd | Real estate | 2017 |
| Siddhrup Accountax Limited | Professional & scientific | 2018 |
| Sideline Pictures Ltd | Information & communication | 2014 |
| Sightsafe (GB) Limited | Construction | 2013 |
| Signum Aviation (Marco) Ltd | Transport & logistics | 2022 |
| Signum Aviation (Marie) Ltd | Financial services | 2025 |
| Silent Defiance Limited | Arts & recreation | 2023 |
| Silent Technology Limited | Wholesale & retail | 2003 |
| Silky Creative Limited | Professional & scientific | 2015 |
| Silverback Design & Build Ltd | Real estate | 2024 |
| Simba Consultancy Limited | Professional & scientific | 2024 |
| Simba Group Investments Ltd | Real estate | 2025 |
| Simba Property Holdings Ltd | Households | 2024 |
| Simister Holdings Ltd | Financial services | 2020 |
| Simon Christopher Electrical Ltd | Construction | 2014 |
| Simple Shipping Solutions Limited | Other services | 2013 |
| Simulovation Ltd | Information & communication | 2025 |
| Since 1987 Limited | Information & communication | 2021 |
| Singla Consultancy Ltd | Information & communication | 2016 |
| Sinq Power Limited | Energy | 2014 |
| Siri Constructions Private Ltd | Manufacturing | 2026 |
| Sirloin PAN Asia Ltd | Hospitality | 2024 |
| Sirloin Steaklounge (Birmingham) Ltd | Hospitality | 2022 |
| Sirloin Steaklounge Holdings Ltd | Hospitality | 2022 |
| Sirloin Steaklounge Ltd | Hospitality | 2016 |
| Site Axis Ltd | Real estate | 2017 |
| Site Civils & Surfacing Ltd | Construction | 2010 |
| Siva Barber Group Ltd | Other services | 2019 |
| SIX Figure Founders Limited | Professional & scientific | 2026 |
| Sixteen Consultancy Ltd | Professional & scientific | 2022 |
| SJ Blueridge Ltd | Real estate | 2025 |