| Service Machine Ltd | Real estate | 2016 |
| Service Management Excellence Ltd | Information & communication | 2017 |
| Service Mandate Limited | Administrative & support | 2017 |
| Serviceco South Ltd | Hospitality | 2020 |
| Serviced Property Rentals Ltd | Hospitality | 2023 |
| Services & Management Company Ltd | Wholesale & retail | 2017 |
| Services in Health Education Limited | Health & social care | 2002 |
| SERVICES121 Limited | Other services | 2025 |
| SERVICES2CONSTRUCT Ltd. | Information & communication | 2015 |
| Servo Services Inc Limited | Professional & scientific | 2015 |
| Serytech Ltd | Professional & scientific | 2025 |
| Sestek Solutions Ltd | Wholesale & retail | 2021 |
| SET Sail Solutions Ltd | Professional & scientific | 2024 |
| Seth Phillips Music Ltd | Information & communication | 2025 |
| Setllo Services Ltd | Administrative & support | 2024 |
| Setpiecesuk Limited | Construction | 2024 |
| Setright Construction Ltd | Other services | 2016 |
| Setsoyu Ltd | Wholesale & retail | 2025 |
| Settemarket Ltd | Information & communication | 2025 |
| Seval Zelal Limited | Hospitality | 2019 |
| Sevco 1106 Limited | Real estate | 1999 |
| Sevco 5051 Limited | Wholesale & retail | 2011 |
| Sevco 5065 Limited | Real estate | 2011 |
| Seven BOT Limited | Manufacturing | 2021 |
| Seven Continents Group Limited | Information & communication | 2021 |
| Seven Dimensions Care Ltd | Health & social care | 2020 |
| Seven Equity Ltd | Real estate | 2024 |
| Seven Financial UK Limited | Financial services | 2007 |
| Seven Hills Group Ltd | Information & communication | 2025 |
| Seven Hills Story Limited | Information & communication | 2025 |
| Seven Rain Food Ltd | Wholesale & retail | 2024 |
| Seven Scaffolding Limited | Construction | 2020 |
| Seven Seal Media Limited | Information & communication | 2023 |
| Seven Steven Limited | Wholesale & retail | 2025 |
| Seven Trent Civil Engineering Ltd | Construction | 2023 |
| Seven-T-One Limited | Professional & scientific | 2011 |
| Sevenk Investments Ltd | Real estate | 2023 |
| Sevenoaks Joinery Ltd | Construction | 2011 |
| SEVENS7 Limited | Other services | 2024 |
| Sevenstarscontractors Limited | Construction | 2022 |
| Sevenstones Developments Limited | Construction | 2019 |
| SEVENTEEN88 Ltd | Information & communication | 2015 |
| Seventh Cornerstone Ltd | Health & social care | 2022 |
| Severn Acres Property Limited | Real estate | 2020 |
| Severn Bay Corporate Solutions Ltd | Financial services | 2010 |
| Severn Burton Ltd | Information & communication | 2024 |
| Severn Denmark Ltd | Information & communication | 2016 |
| Severn Estuary Tidal Bar Limited | Professional & scientific | 2020 |
| Severn Financial Ltd | Financial services | 2022 |
| Severn Fires Ltd | Wholesale & retail | 2010 |
| Severn Furnace Ltd | Information & communication | 2024 |
| Severn House Cardiff Ltd | Administrative & support | 2015 |
| Severn Insulation EOT Trustee Limited | Financial services | 2026 |
| Severn Lluest Limited | Information & communication | 2026 |
| Severn Mudtown Ltd | Information & communication | 2024 |
| Severn Offshore Ltd | Transport & logistics | 2019 |
| Severn Offshore Services Ltd | Transport & logistics | 2014 |
| Severn Realtors Ltd | Real estate | 2019 |
| Severn River Environmental Limited | Water & waste | 2018 |
| Severn Road Old Bakery Management Company Limited | Households | 2004 |
| Severn Road Residents Management Company Limited | Households | 2017 |
| Severn Sails Ltd | Manufacturing | 2026 |
| Severn Screen Ltd. | Information & communication | 2008 |
| Severn Social Limited | Hospitality | 2017 |
| Severn STM Limited | Information & communication | 2022 |
| Severn Technologies Ltd | Information & communication | 2024 |
| Severnside Car Company Ltd | Wholesale & retail | 2015 |
| Sevser Ltd | Wholesale & retail | 2025 |
| Sevyn X Beauty Ltd | Other services | 2025 |
| SEW on and SEW Forth Ltd | Wholesale & retail | 2016 |
| Sewarz Ltd | Wholesale & retail | 2025 |
| Sewer Surveys UK Ltd | Water & waste | 2015 |
| Sewonzo Ltd | Wholesale & retail | 2025 |
| Sextant Group Ltd | Administrative & support | 2020 |
| Sexton Materials Research Limited | Professional & scientific | 2016 |
| Sexy Super Star Limited | Wholesale & retail | 2025 |
| Seyhmus Onur Limited | Wholesale & retail | 2025 |
| Seymour Mode Ltd | Wholesale & retail | 2026 |
| Seyra Ltd | Wholesale & retail | 2025 |
| Seysez Ltd | Wholesale & retail | 2025 |
| Seyubi Ltd | Wholesale & retail | 2025 |
| SEZ Social Care Services Limited | Health & social care | 2013 |
| Sezer Homes Ltd | Households | 2024 |
| SF Cart Hub Ltd | Wholesale & retail | 2025 |
| SF Devon Limited | Other services | 2020 |
| SFA Investments Ltd | Construction | 2025 |
| SFA Ventures Ltd | Agriculture & fishing | 2018 |
| Sfalara Solutions Ltd | Administrative & support | 2021 |
| SFC Engineering Ltd | Professional & scientific | 2021 |
| Sfdb Digital Ltd | Information & communication | 2020 |
| Sfdb Recording Limited | Information & communication | 2015 |
| Sfft Ltd | Professional & scientific | 2026 |
| Sffys Ltd | Wholesale & retail | 2025 |
| SFH Optics Limited | Health & social care | 2024 |
| SFK Smile Ltd | Health & social care | 2022 |
| Sfsocialcareservices Limited | Health & social care | 2022 |
| SFT Agencies Limited | Other services | 2009 |
| SFW Consulting Limited | Professional & scientific | 2024 |
| SFX Technology Ltd. | Wholesale & retail | 2004 |
| SG Autosales Ltd | Wholesale & retail | 2022 |