| SJ VIP Limited | Real estate | 2024 |
| SJA Capital Ltd | Financial services | 2026 |
| SJB Goalkeeping Limited | Arts & recreation | 2023 |
| SJC Productions Ltd | Manufacturing | 2021 |
| SJG Movement Ltd | Arts & recreation | 2023 |
| Sjjt Services Ltd | Information & communication | 2026 |
| Sjkm Colorectal Surgery Limited | Health & social care | 2020 |
| SJT Management Ltd | Professional & scientific | 2016 |
| Skechers Ukdc Limited | Transport & logistics | 2020 |
| SKI Snowcoach Limited | Hospitality | 2009 |
| Skillsync AI Limited | Information & communication | 2025 |
| Skin & Tonic Beauty Salon Limited | Other services | 2003 |
| Skin 65 Limited | Wholesale & retail | 2021 |
| Skin Angels Herts Ltd | Other services | 2024 |
| Skin Hub ST Albans Limited | Other services | 2022 |
| Skin Medics Herts Brighton Limited | Other services | 2020 |
| Skin Medics Herts Limited | Other services | 2021 |
| Skinartsoul Ltd | Professional & scientific | 2025 |
| Skip Brands Limited | Manufacturing | 2023 |
| Skip Gallery Limited | Arts & recreation | 2017 |
| SKM Designs Limited | Professional & scientific | 2013 |
| Skratchr Limited | Information & communication | 2025 |
| SKS Contractors Ltd | Construction | 2014 |
| Sktb & SON Ltd | Wholesale & retail | 2020 |
| SKTR19 Limited | Information & communication | 2013 |
| Sky Bridge Consultants Ltd | Professional & scientific | 2024 |
| Sky Contractors Ltd | Construction | 2023 |
| Skybridge Advisory Limited | Professional & scientific | 2024 |
| Skyline Hub Prime Limited | Construction | 2026 |
| Skylon Electrical Ltd | Construction | 2023 |
| Skylon Elements Limited | Construction | 2024 |
| Skyswood Ltd | Wholesale & retail | 2023 |
| SL Design and Build Ltd | Construction | 2019 |
| SL Endeavours Limited | Financial services | 2012 |
| SL Truck and Trailer Limited | Manufacturing | 2019 |
| Slam Signs Limited | Manufacturing | 2014 |
| Slateriver Group Limited | Construction | 2024 |
| SLC Creative Ltd | Extraterritorial | 2019 |
| Sleep & Snoring Limited | Health & social care | 2024 |
| Sleepy Girl ERA Ltd | Wholesale & retail | 2025 |
| SLG Retail UK Ltd | Wholesale & retail | 2025 |
| Slim Investments Limited | Financial services | 2016 |
| Slim Wallet Ltd | Wholesale & retail | 2016 |
| Slipstream Creative Agency Ltd | Construction | 2020 |
| Slow Baking Ltd | Wholesale & retail | 2018 |
| Slpractice Ltd | Information & communication | 2026 |
| SM & J Homes Ltd | Real estate | 2025 |
| SM Autos Ltd | Wholesale & retail | 2006 |
| Small Animal Neurology and Neurosurgery Care by JJ Mínguez Ltd | Professional & scientific | 2019 |
| Small Margins Limited | Manufacturing | 2025 |
| Smalley S&C Limited | Arts & recreation | 2026 |
| Smart Clothing Ltd | Wholesale & retail | 2025 |
| Smart Construction 76 Limited | Construction | 2015 |
| Smart Short Stays Limited | Hospitality | 2023 |
| Smart Solutions Training Ltd | Health & social care | 2012 |
| Smart TM Ltd | Administrative & support | 2017 |
| Smartchoice Solutions International Limited | Administrative & support | 2020 |
| Smarter Direct Limited | Professional & scientific | 1995 |
| Smartforms Ltd | Information & communication | 2014 |
| Smartplc.Com Ltd | Construction | 2024 |
| Smash Global Limited | Wholesale & retail | 2012 |
| SMB 2001 Ltd | Construction | 2020 |
| Smdj Trading Limited | Administrative & support | 2012 |
| SME Summits Limited | Education | 2011 |
| Smith Glass Limited | Manufacturing | 2002 |
| Smith Utilities Ltd | Construction | 2025 |
| Smlxl Consultants Ltd | Professional & scientific | 2017 |
| Smokfree Lozells Limited | Health & social care | 2024 |
| SMQ Legal Services LLP | | 2014 |
| Smug Sure Limited | Administrative & support | 2009 |
| SMY Kurd Ltd | Wholesale & retail | 2025 |
| Snap Hertfordshire Limited | Health & social care | 2006 |
| SNG Surveying Services Ltd | Professional & scientific | 2013 |
| Snitch Ltd | Information & communication | 2025 |
| SNJ Private Hire Limited | Transport & logistics | 2025 |
| Snmz Ltd | Manufacturing | 2026 |
| SNN Solution Ltd | Professional & scientific | 2012 |
| Snowbreaks Limited | Wholesale & retail | 2016 |
| Snug Solutions Ltd. | Manufacturing | 2014 |
| Snugora Limited | Wholesale & retail | 2026 |
| SO Pretty Limited | Wholesale & retail | 2021 |
| Socare Limited | Administrative & support | 2014 |
| Soccer Elite Tours Limited | Administrative & support | 2019 |
| Socialburst Limited | Information & communication | 2022 |
| Socially Frankie Limited | Administrative & support | 2021 |
| Socially Recruited Ltd | Professional & scientific | 2017 |
| Sociotechnic Limited | Professional & scientific | 2009 |
| Socius Projects Ltd | Construction | 2014 |
| Sock Puppet Productions Ltd | Professional & scientific | 2022 |
| Sockett Refrigeration & Air Conditioning Ltd | Construction | 2026 |
| Soft Revolution Ltd | Information & communication | 2026 |
| Softkey Solutions Ltd | Information & communication | 2021 |
| SOH Express Limited | Hospitality | 2022 |
| Sohotech Ltd | Information & communication | 2020 |
| Soil Squad CIC | Agriculture & fishing | 2024 |
| SOL Power RE Ltd | Information & communication | 2010 |
| Sola Renewable Company Ltd | Construction | 2020 |
| Solace Distribution Ltd | Wholesale & retail | 2026 |
| Solange Concept Salon and Spa Ltd | Other services | 2025 |
| Solar Projects Ltd | Construction | 2023 |