| SLG Consultants Limited | Professional & scientific | 2025 |
| Slicertechnology Limited | Professional & scientific | 2018 |
| Slick Healthcare Limited | Wholesale & retail | 2025 |
| Slickify Ltd | Information & communication | 2024 |
| Sling Therapeutics UK Limited | Professional & scientific | 2026 |
| Slipstream UK Opco Ltd | Information & communication | 2024 |
| Slkhan Limited | Health & social care | 2013 |
| SLM & RLM Lettings Limited | Real estate | 2019 |
| Sloan & Associates Limited | Real estate | 2013 |
| Sloan FM Limited | Real estate | 2019 |
| Sloan Property Company Limited | Real estate | 2018 |
| Slowmo Limited | Professional & scientific | 2003 |
| SM & BJ Finance Limited | Professional & scientific | 2024 |
| SM Aviation Services Limited | Professional & scientific | 2026 |
| SM Orthopaedics Limited | Health & social care | 2017 |
| SM Property & Investments Ltd | Real estate | 2026 |
| SM0 Capital & Security Limited | Financial services | 2025 |
| SM1 Capital & Security Limited | Financial services | 2020 |
| SM3 Capital & Security Limited | Financial services | 2025 |
| SM4 Capital & Security Limited | Financial services | 2025 |
| SM5 Capital & Security Limited | Financial services | 2025 |
| SM6 Capital & Security Limited | Financial services | 2025 |
| Smacanalytics Limited | Information & communication | 2023 |
| Small and Small Music Limited | Education | 2025 |
| Small Space Bathrooms Ltd | Construction | 2019 |
| Small Talk Salt Limited | Administrative & support | 2014 |
| Smallworldwide Limited | Financial services | 1988 |
| Smama Ltd | Real estate | 2025 |
| Smaran Ltd | Education | 2018 |
| Smart Convey Limited | Administrative & support | 2025 |
| Smart Cookie Tuition Limited | Education | 2019 |
| Smart ID Ltd | Real estate | 2020 |
| Smart Risk Limited | Other services | 2015 |
| Smart SOL Services Ltd | Administrative & support | 2019 |
| Smart Solutions (SCM) Limited | Professional & scientific | 2008 |
| Smart Solutions Consulting Engineers Ltd | Professional & scientific | 2022 |
| Smart Storage (Altrincham) Limited | Real estate | 2015 |
| Smart Storage (Liverpool) Limited | Real estate | 2015 |
| Smart Storage Holdings Limited | Real estate | 2013 |
| Smart-Storage Limited | Real estate | 2004 |
| Smarter Creative Studio Ltd | Wholesale & retail | 2024 |
| Smash Parties Ltd | Other services | 2019 |
| Smash Pizzeria Ltd | Hospitality | 2025 |
| Smcj Ltd | Health & social care | 2023 |
| SME Business Solutions Ltd | Professional & scientific | 2007 |
| SME Prosthodontics Ltd | Education | 2020 |
| SMG Smiles Ltd | Health & social care | 2022 |
| Smg-Cf Limited | Professional & scientific | 2008 |
| SMH Management Ltd | Hospitality | 2012 |
| SMH Medical Communications Limited | Professional & scientific | 2020 |
| SMH Property Ltd | Real estate | 2023 |
| Smile Chic Ltd | Health & social care | 2019 |
| Smiles by SAM Ltd | Health & social care | 2024 |
| Smith & Abbott Limited | Financial services | 2015 |
| Smith Executive Management Limited | Professional & scientific | 2024 |
| Smithfield Performance Limited | Professional & scientific | 2005 |
| Smitsons Ltd | Energy | 2018 |
| SMP Nationwide Ltd | Other services | 2017 |
| SMR Procurement Solutions Ltd | Professional & scientific | 2019 |
| Snagworks Limited | Construction | 2005 |
| Snappily Limited | Information & communication | 2022 |
| Snipz (Hale) Limited | Other services | 2012 |
| Snipz Barbers Ltd | Other services | 2026 |
| SNK Solicitors Limited | Professional & scientific | 2016 |
| Snow Wolf Limited | Professional & scientific | 2022 |
| Snowdonia Holiday Cottages Ltd | Hospitality | 2019 |
| Snowripper Ltd | Manufacturing | 2025 |
| SNS Property Ventures Ltd | Real estate | 2024 |
| Snta Group Ltd | Financial services | 2016 |
| SO Marrakech Ltd | Other services | 2018 |
| Soaroc International Limited | Water & waste | 2011 |
| Soccer Scholar USA Limited | Administrative & support | 2017 |
| Soccerwise Limited | Arts & recreation | 2005 |
| Sociable Group Ltd. | Professional & scientific | 2017 |
| Social Landlords Crime and Nuisance Group | Other services | 2000 |
| Social Money Group Limited | Financial services | 2020 |
| Social Money Limited | Financial services | 2012 |
| Social Operative Ltd | Wholesale & retail | 2025 |
| Social Plug Limited | Information & communication | 2017 |
| Social Tonic Limited | Professional & scientific | 2018 |
| Social Value Studio Ltd | Professional & scientific | 2019 |
| Social Work Options Limited | Health & social care | 2017 |
| Socialbakers UK Limited | Information & communication | 2013 |
| Soft Edge Consultants Limited | Professional & scientific | 2024 |
| Soft Muck Ltd | Real estate | 2022 |
| Software and Code Ltd | Information & communication | 2013 |
| Sogni Limited | Construction | 2024 |
| Sohailgastrouk Ltd | Health & social care | 2012 |
| Soho HG1 Limited | Real estate | 2021 |
| Soho HG2 Limited | Construction | 2022 |
| Soho HG3 Limited | Construction | 2022 |
| Soho Orthodontics Ltd | Health & social care | 2018 |
| Soho Paper JV Holdings Limited | Construction | 2022 |
| Soho Paper Limited | Financial services | 2022 |
| Soil Instruments Ltd | Manufacturing | 2012 |
| SOL Property Investments Limited | Real estate | 2017 |
| Solace Massage Therapy Ltd | Arts & recreation | 2023 |
| Solace Orthopaedic Solutions+ Ltd | Health & social care | 2024 |
| Solann Limited | Real estate | 2025 |
| Solaraconnect Energy Ltd | Professional & scientific | 2025 |