| Sellectlets. Ltd. | Real estate | 2008 |
| Selsse Solar Holdings II Limited | Energy | 2021 |
| Selsse Solar Holdings III Limited | Energy | 2021 |
| Selt Property Holdings Limited | Real estate | 2018 |
| Seltasports Limited | Wholesale & retail | 2024 |
| Seltaway Limited | | 1975 |
| Selty Investment Ltd | Real estate | 2022 |
| Selvam Property Ltd | Real estate | 2024 |
| Selwood Enterprises Limited | Transport & logistics | 2004 |
| SEM Access Ltd | Construction | 2021 |
| Semantech Group Limited | Information & communication | 2015 |
| Semantech Limited | Information & communication | 2015 |
| Semelab Limited | Manufacturing | 2008 |
| Semelif Health Consultancy Ltd | Hospitality | 2021 |
| Semi Megacorp Ltd | Wholesale & retail | 2025 |
| Semla Scandinavian Bakery Club Ltd | Hospitality | 2025 |
| Semper Invicta Ltd | Information & communication | 2019 |
| Sena Electrical Ltd | Construction | 2024 |
| Senafesolutions Ltd | Wholesale & retail | 2023 |
| Senate (Construction Services) Limited | Construction | 2015 |
| Senate Group (Topco) Limited | Financial services | 2021 |
| Senate Group Holdings Limited | Real estate | 2017 |
| Senate Group Ltd | Financial services | 2024 |
| Senate Mech Limited | Construction | 2002 |
| Senator Services Limited | Transport & logistics | 2020 |
| Sencan Limited | Administrative & support | 2013 |
| Senchi Beauty Ltd | Wholesale & retail | 2025 |
| Sendabc Limited | Administrative & support | 2020 |
| Sendscope Consultancy Ltd | Professional & scientific | 2025 |
| Sendscope Ltd | Education | 2021 |
| Senegambia Cuisine Limited | Wholesale & retail | 2024 |
| Senelux Ltd | Administrative & support | 2016 |
| Senelux U.K. Limited | Wholesale & retail | 2023 |
| Senior Active Independence Limited | Health & social care | 2025 |
| Senior Care at Home Ltd | Health & social care | 2009 |
| Senlim Oilfield Logistics Limited | Mining & quarrying | 2018 |
| Senna International Limited | Hospitality | 2022 |
| Sensation Bars Ltd | Hospitality | 2021 |
| Senseai Vision Limited | Information & communication | 2023 |
| Sensified Spaces Ltd | Information & communication | 2025 |
| Sensor City Liverpool Ltd | Professional & scientific | 2014 |
| Sensoria Communications Limited | Information & communication | 2004 |
| Sensoriel CIC | Health & social care | 2011 |
| Sensory Creative LAB CIC | Education | 2026 |
| Sensory Miyagi CIC | Professional & scientific | 2025 |
| Sensory Swim & Health Merseyside CIC | Other services | 2018 |
| Sentience Ltd | Information & communication | 2022 |
| Sentinam Properties Limited | Construction | 2019 |
| Sentinel Cctv Ltd | Administrative & support | 2025 |
| Sentinel Electrics Limited | Construction | 2008 |
| Sentinel Safeguarding Consultancy Ltd | Professional & scientific | 2025 |
| Sentinel Site & Safety Ltd | Real estate | 2021 |
| Sentosa Estates Limited | Real estate | 2025 |
| Sentosa Lettings Ltd | Real estate | 2024 |
| Sentosa Properties Ltd | Real estate | 2023 |
| Sentric Music Group Limited | Arts & recreation | 2020 |
| Sentric Music Limited | Arts & recreation | 2006 |
| Sentric Music Publishing Ltd | Information & communication | 2011 |
| Senuna Global Ltd | Wholesale & retail | 2024 |
| Senyab Properties Limited | Real estate | 2001 |
| SEO Domains Ltd | Information & communication | 2026 |
| Sephora Beauty Ltd | Other services | 2012 |
| Sephora Medispa Ltd | Other services | 2021 |
| Sepia Management Co. Limited | Households | 2001 |
| Sepsiscan Limited | Manufacturing | 2026 |
| Sequoia Group Holdings Ltd | Financial services | 2018 |
| Sequoia Health Limited | Professional & scientific | 2017 |
| Seraph Wellbeing Hub Community Interest Company | Education | 2025 |
| Seraphina Executive Travel Ltd | Administrative & support | 2026 |
| Seren Fraud Consulting Ltd | Professional & scientific | 2025 |
| Seren Operations Limited | Financial services | 2026 |
| Seren Retreats 1 Limited | Real estate | 2024 |
| Seren Retreats 2 Limited | Real estate | 2025 |
| Seren Retreats 3 Limited | Real estate | 2025 |
| Seren Retreats 4 Limited | Real estate | 2025 |
| Seren Retreats 5 Limited | Real estate | 2026 |
| Seren Support Limited | Health & social care | 2024 |
| Serenade 1962 Limited | Extraterritorial | 2013 |
| Serendipity App Company Ltd | Information & communication | 2015 |
| Serendipity Scripts Ltd | Arts & recreation | 2024 |
| Serendipity Vintage Ltd | Wholesale & retail | 2025 |
| Serene Garden Ltd | Health & social care | 2021 |
| Serene Haus Ltd | Real estate | 2021 |
| Serene Health & Care Ltd | Public administration | 2024 |
| Serene Hideaways Ltd | Hospitality | 2025 |
| Serenity Approach Limited | Administrative & support | 2024 |
| Serenity Briars Hall Beauty Barn Ltd | Other services | 2015 |
| Serenity Clinic Limited | Other services | 2002 |
| Serenity Cyber Security Ltd | Information & communication | 2019 |
| Serenity Mountaineering Limited | Arts & recreation | 2026 |
| Serenity Scalp Clinic UK Limited | Other services | 2024 |
| Serenity Spa Formby Ltd | Other services | 2014 |
| Serenity Suites 2 Limited | Households | 2025 |
| Serenitystudiouk Limited | Arts & recreation | 2023 |
| Sergeant Property Holdings Ltd | Real estate | 2023 |
| Sergeant Property Investments Ltd | Real estate | 2023 |
| Serious Nutrition Ltd | Wholesale & retail | 2017 |
| Seronok Books Limited | Information & communication | 2015 |
| Serpa Management Ltd | Administrative & support | 2026 |
| Serro Labs Ltd | Information & communication | 2025 |