| Smartg Partners LLP | | 2026 |
| Smartg Technology Ltd | Administrative & support | 2016 |
| Smartselluk Limited | Wholesale & retail | 2024 |
| Smear Free Limited | Administrative & support | 2011 |
| Smile Hub Ltd | Health & social care | 2023 |
| Smkh Properties Ltd | Real estate | 2023 |
| SML Accountancy Services Limited | Professional & scientific | 2010 |
| Smokey Joe's Diner Limited | Extraterritorial | 1998 |
| Smoky Signal Limited | Professional & scientific | 2024 |
| Smugg Limited | Arts & recreation | 2007 |
| SMZ Solutions U.K. Ltd | Administrative & support | 2025 |
| SN Surrey Consulting Ltd | Professional & scientific | 2025 |
| Snapp CV Group PLC | Information & communication | 2019 |
| Snapp CV Ltd | Information & communication | 2014 |
| Snapper Services (UK) Limited | Financial services | 2021 |
| Sneaton Holdings Limited | Hospitality | 2024 |
| Snow Cloud Technology UK Limited | Professional & scientific | 2023 |
| Snow Hill Advisors Ltd | Professional & scientific | 2013 |
| Snozex Carpentry Ltd | Construction | 2022 |
| Snpuk Ltd | Other services | 2020 |
| SO Like US Limited | Real estate | 2016 |
| SOA Group Limited | Information & communication | 2021 |
| SOA Project Management Ltd | Administrative & support | 2021 |
| Social Clothing Ltd | Wholesale & retail | 2021 |
| Social Empowerment Ltd | Real estate | 2016 |
| Social Good Property Holdings Ltd | Real estate | 2025 |
| Social Promotions Limited | Wholesale & retail | 2012 |
| Sockertopp Trading Limited | Real estate | 2017 |
| Soggy Dollar Limited | Hospitality | 2018 |
| SOL & Sun Limited | Professional & scientific | 2020 |
| SOL VIP Service Ltd | Administrative & support | 2025 |
| Sold Short (Marketing) Ltd | Professional & scientific | 2026 |
| Sole Food Ltd | Wholesale & retail | 2019 |
| Solid Gold Marketing Services Limited | Professional & scientific | 2026 |
| Solitude LAB Ltd. | Professional & scientific | 2025 |
| Solo Media Limited | Information & communication | 2014 |
| Solution 106 Limited | Households | 2002 |
| Solution Pursuits Limited | Information & communication | 2010 |
| Solutions (Co) Ltd | Construction | 2007 |
| Solvesmith Ltd | Professional & scientific | 2026 |
| Some 1 Else Services Ltd | Financial services | 2024 |
| Somers Close Freehold Limited | Households | 2005 |
| Somers Hills Limited | Manufacturing | 2017 |
| Somers UK (Holdings) Limited | Financial services | 2014 |
| Sonam Galaxy Ltd | Wholesale & retail | 2023 |
| Sonatco Limited | Financial services | 2025 |
| Sonicproducts Ltd | Manufacturing | 2019 |
| Sons of Energy Ltd | Construction | 2025 |
| Sossage Factory Company Ltd | Real estate | 2022 |
| Soteria Collective CIC | Education | 2026 |
| Soulfunk Ltd | Manufacturing | 2018 |
| Soulnote Limited | Information & communication | 2025 |
| Sound Resource Ltd | Professional & scientific | 2002 |
| Sound Ventures Limited | Households | 2017 |
| Sound X Advice Ltd | Professional & scientific | 2020 |
| Source Rail Ltd | Administrative & support | 2019 |
| South B Ltd | Real estate | 2021 |
| South France Holiday Villas Limited | Hospitality | 2011 |
| South London Party Wall Surveyors Ltd | Construction | 2016 |
| South Thames Decorating Limited | Construction | 2019 |
| South Thames Electrical Contractors Limited | Construction | 2007 |
| South Thames Roofing Ltd | Construction | 2010 |
| South Thames Waste Removal Ltd | Water & waste | 2024 |
| South West Strategic Developments Limited | Professional & scientific | 2013 |
| Southern Fire Engineering Limited | Construction | 2016 |
| Southern Oaks Retirement Living | Health & social care | 1962 |
| Southern Property Information Limited | Professional & scientific | 2015 |
| Southern Toughening & Glazing Ltd | Construction | 2014 |
| Soxiety Limited | Wholesale & retail | 2011 |
| SP Cabling & Installations Ltd | Construction | 1998 |
| SP Global Trade Ltd | Wholesale & retail | 2025 |
| Spa Cardiac Ltd | Health & social care | 2025 |
| Space DEV Labs Ltd | Information & communication | 2022 |
| Space Managers Limited | Administrative & support | 2023 |
| Spacepole Limited | Information & communication | 2004 |
| Spark UP the Fire Ltd | Extraterritorial | 2020 |
| Sparkmind Retail Ltd | Wholesale & retail | 2025 |
| Sparksfly Limited | Professional & scientific | 2019 |
| Sparksync Ltd | Professional & scientific | 2016 |
| Sparrowbrook Lighting Design Ltd | Professional & scientific | 2025 |
| Spartan Contractors Ltd | Construction | 2026 |
| Spasht Ltd | Hospitality | 2025 |
| SPC Installations Limited | Extraterritorial | 2010 |
| Speakup-Beheard Ltd | Professional & scientific | 1995 |
| Specgases Limited | Manufacturing | 2020 |
| Specialist Blinds Limited | Administrative & support | 2017 |
| Specialist Glass Repairs Ltd | Wholesale & retail | 2013 |
| Specialist Glass Repairs UK Limited | Professional & scientific | 2015 |
| Specktrum Consultancy Services Ltd | Professional & scientific | 2006 |
| Spectrum Residential Services Limited | Construction | 2005 |
| Speedvan UK Services Ltd | Transport & logistics | 2022 |
| Speedwell Music Limited | Information & communication | 2022 |
| Speeedy Aiders Ltd | Education | 2023 |
| Speklr Ltd | Information & communication | 2026 |
| Spencer Mews W6 Management Limited | Households | 2018 |
| Speystead Court Residents Limited | Households | 1991 |
| Spherically Ltd | Professional & scientific | 2020 |
| Spice Hub (Epsom) Ltd | Administrative & support | 2018 |
| Spicentra Ltd | Hospitality | 2025 |
| Spider Rope Access Ltd | Construction | 2019 |