| Secops Ltd | Information & communication | 2016 |
| Secret Garden Aquatics & Horticultural Supplies Ltd | Agriculture & fishing | 2018 |
| Secret GIN Ltd | Hospitality | 2019 |
| Secret Sauce Marketing Limited | Professional & scientific | 2016 |
| Secret Source Marketing Limited | Professional & scientific | 2015 |
| Secret Speed Ltd | Wholesale & retail | 2024 |
| Secrets Squared Limited | Information & communication | 2016 |
| Sector Processing Ltd | Information & communication | 2026 |
| Sectr Sports Management Limited | Arts & recreation | 2025 |
| Securatech Projects Limited | Professional & scientific | 2026 |
| Secure Car Solutions Ltd | Wholesale & retail | 2024 |
| Secure First FM Ltd | Administrative & support | 2017 |
| Secure Health Ltd | Health & social care | 2018 |
| Secure Step Forward Ltd | Information & communication | 2022 |
| Secure Vission Limited | Administrative & support | 2019 |
| Security CPD Global Ltd | Education | 2021 |
| Security Group Services Ltd | Administrative & support | 2018 |
| Security MEN Ltd | Financial services | 2018 |
| Sedgebrook Motors Ltd | Wholesale & retail | 2026 |
| Sedve Haulage Ltd | Transport & logistics | 2017 |
| Seed and Straw Ltd | Manufacturing | 2017 |
| Seedlink Import Export Ltd | Agriculture & fishing | 2024 |
| Seegi Limited | Professional & scientific | 2021 |
| Seerise Ltd. | Information & communication | 2014 |
| Sefton Rail Engineering Limited | Professional & scientific | 2019 |
| Segida Limited | Health & social care | 2019 |
| Segomo Co Ltd | Wholesale & retail | 2025 |
| Sekasua Engineering Ltd | Professional & scientific | 2023 |
| Sekko Ltd | Wholesale & retail | 2023 |
| Selby Accountancy Limited | Professional & scientific | 2019 |
| Select Coffee Group Ltd | Wholesale & retail | 2022 |
| Select Woodworks Limited | Construction | 2021 |
| Selectnowandshop Limited | Wholesale & retail | 2024 |
| Selen Inter Trans Ltd | Transport & logistics | 2024 |
| Self Made Haulage Limited | Transport & logistics | 2025 |
| Sellickrail Limited | Professional & scientific | 2016 |
| Sellmycaronlinenow Ltd | Wholesale & retail | 2025 |
| Selloworld Ltd | Wholesale & retail | 2025 |
| Semi-Independent House Limited | Health & social care | 2008 |
| SEN Logistics Ltd | Transport & logistics | 2024 |
| SEN4YOU Limited | Extraterritorial | 2014 |
| Send.Blue Limited | Information & communication | 2016 |
| SEND24 Ltd | Transport & logistics | 2017 |
| Sendsational Moves Ltd | Arts & recreation | 2024 |
| Seneca Living Ltd | Real estate | 2025 |
| Seneca Search Ltd | Administrative & support | 2008 |
| Senojah Ltd | Arts & recreation | 2024 |
| Sensation Creative Limited | Information & communication | 2013 |
| Sense Properties Limited | Real estate | 2018 |
| Sentinel Business IT Ltd | Information & communication | 2006 |
| Sentinel Motor Group Limited | Wholesale & retail | 2025 |
| Seom Skincare Limited | Wholesale & retail | 2024 |
| Sepm Transformers Limited | Manufacturing | 2020 |
| Sequoia Midstream Incorporated Ltd | Manufacturing | 2024 |
| Seraphina Enterprises Limited | Hospitality | 2023 |
| Serendip Publishers Limited | Information & communication | 1996 |
| Serene Abode Ltd | Real estate | 2017 |
| Serenity Education Group Limited | Financial services | 2025 |
| Serenity Furnishings Ltd | Wholesale & retail | 2025 |
| Serenity Loves Franchising Limited | Other services | 2014 |
| Serenity Loves Limited | Other services | 2011 |
| Serenity Senior Concierge Ltd | Hospitality | 2026 |
| Serenitygold Healthcare Ltd | Health & social care | 2025 |
| Seriway Technology Ltd | Information & communication | 2013 |
| Sertek Peterborough Limited | Transport & logistics | 2021 |
| Service MAN Limited | Other services | 2025 |
| Service Management Solutions (SMS) Limited | Information & communication | 2003 |
| Service-Av Property Limited | Real estate | 2025 |
| Servisdent Limited | Other services | 2017 |
| SES Plants Ltd | Wholesale & retail | 2024 |
| Setchfield Associates Limited | Construction | 2001 |
| Setchfield Investment Ltd | Financial services | 2026 |
| Setchfield Services Limited | Administrative & support | 2021 |
| Sethi Investments Limited | Real estate | 2002 |
| Setiara Ltd | Health & social care | 2023 |
| Sett Rcrds Ltd | Information & communication | 2025 |
| Settled by MIA Limited | Other services | 2025 |
| Settys Ltd | Wholesale & retail | 2008 |
| Setubal Bar Ltd | Wholesale & retail | 2016 |
| Sevara Advisors Ltd | Information & communication | 2026 |
| Seven Property Investments Ltd | Real estate | 2019 |
| Seven Seasons Limited | Wholesale & retail | 2014 |
| Seventh Air Ltd | Extraterritorial | 2023 |
| Sevid&Uk Ltd | Wholesale & retail | 2025 |
| Sevita Holdings Limited | Financial services | 2022 |
| Sevita Holidays Limited | Real estate | 2020 |
| Sevita Investments Limited | Real estate | 2017 |
| Sevita Properties Limited | Real estate | 2020 |
| Seymour Distribution Limited | Wholesale & retail | 1994 |
| Seymour International Limited | Wholesale & retail | 1994 |
| Sezh Management Ltd | Wholesale & retail | 2020 |
| SF, Property Maintenance & Decoration Ltd | Construction | 2021 |
| Sf-Pbo Ltd | Wholesale & retail | 2019 |
| SFM123 Ltd | Hospitality | 2022 |
| SFR 2023 Ltd | Hospitality | 2023 |
| SFR Electric Ltd | Construction | 2024 |
| SFT Associates Limited | Professional & scientific | 2011 |
| SG Computing Limited | Wholesale & retail | 2013 |
| SG Dryliners Limited | Construction | 2024 |
| SG Fire Limited | Construction | 2020 |