| SN12 6EF Limited | Energy | 2014 |
| Snappyhandcarwash Limited | Administrative & support | 2025 |
| Sneakers Place Ltd | Professional & scientific | 2015 |
| Snow Problem Ltd | Administrative & support | 2021 |
| SNS Project Consulting Ltd | Professional & scientific | 2025 |
| SNS WRC Ltd | Hospitality | 2024 |
| SO Chic Interiors Ltd | Real estate | 2004 |
| SO Chic Ltd | Wholesale & retail | 2004 |
| Socialclimb Marketing Ltd | Professional & scientific | 2025 |
| Software Dialog Direct Limited | Information & communication | 2003 |
| Soho Develop Limited | Construction | 2024 |
| Solar Warrior Ltd | Construction | 2010 |
| Solarax Ltd | Wholesale & retail | 2023 |
| Solera Properties Limited | Real estate | 2025 |
| Sollus Limited | Professional & scientific | 2025 |
| Sony Bedroom and Kitchen Ltd | Manufacturing | 2024 |
| Sophias Security Ltd | Administrative & support | 2021 |
| Sophie Loya Limited | Administrative & support | 2024 |
| Sophira Group Ltd | Wholesale & retail | 2020 |
| Soricilda Ltd | Real estate | 2021 |
| Soteria Property Management Ltd | Households | 2020 |
| Sound Copy Ltd | Professional & scientific | 2020 |
| Source Data Management Limited | Information & communication | 2018 |
| South Hills Limited | Administrative & support | 2022 |
| South Lodge Management Company (Ascot) Limited | Households | 2008 |
| Southbrook Media Management Limited | Real estate | 1997 |
| Southern GAS and Power Ltd | Professional & scientific | 2021 |
| Southern Motorhome Centre Ltd | Wholesale & retail | 1999 |
| Southern Pneumatics Limited | Manufacturing | 1993 |
| Southwest IT Services Ltd | Information & communication | 2022 |
| Sovereign Autos Ltd | Wholesale & retail | 2024 |
| Sovereign Capital Ltd | Financial services | 2025 |
| Sovereign Empire Ltd | Real estate | 2025 |
| Sovereign Flat Management Limited | Households | 2008 |
| Sovereign Haulage Ltd | Transport & logistics | 2023 |
| Sovereign Marketing Ltd | Professional & scientific | 2025 |
| Soya Oriental Takeaway Limited | Hospitality | 2004 |
| Space 4 U Self Storage Limited | Transport & logistics | 2007 |
| Spanish BIT Riding School Limited | Education | 2002 |
| Sparkdogmedia Ltd | Professional & scientific | 2024 |
| Sparkle & Light Limited | Wholesale & retail | 2011 |
| Sparkling Luxury Cleaning Co. Ltd | Administrative & support | 2025 |
| Sparta Decor Limited | Wholesale & retail | 2017 |
| Sparta Statues Limited | Wholesale & retail | 2014 |
| Specialist Arts Ltd | Education | 2024 |
| Specialize Education Limited | Professional & scientific | 2024 |
| Specialized Roofing and Building Ltd | Construction | 2026 |
| SPECWASHIP2007 Limited | Professional & scientific | 2007 |
| Spice & Aroma Limited | Hospitality | 2025 |
| Spiked FS Ltd | Arts & recreation | 2012 |
| Spirit Energy Limited | Financial services | 2017 |
| Spirit Energy North Sea Limited | Mining & quarrying | 2002 |
| Spirit Energy Production UK Limited | Mining & quarrying | 1995 |
| Spirit Energy Resources Limited | Mining & quarrying | 1993 |
| Spirit Energy Southern North Sea Limited | Mining & quarrying | 2006 |
| Spirit Energy Treasury Limited | Professional & scientific | 2017 |
| Spirit Europe Limited | Mining & quarrying | 2004 |
| Spirit Norway Limited | Professional & scientific | 2006 |
| Spirit Resources (Armada) Limited | Mining & quarrying | 2001 |
| Spoderye Limited | Households | 1973 |
| Sports Facility Planning & Design Limited | Professional & scientific | 2010 |
| Spot on Electrics Ltd. | Construction | 2016 |
| Spread Services Limited | Construction | 2018 |
| Spring CPO Limited | Professional & scientific | 2016 |
| Spring Gardens (High Wycombe) Management Company Limited | Households | 2005 |
| Spring Rise (Egham) Management Company Limited | Households | 1998 |
| Sprintf Limited | Information & communication | 2010 |
| Spritz Holdings Ltd | Financial services | 2023 |
| Sprout Investments Limited | Real estate | 2025 |
| Sprouting Sprogs Ltd | Health & social care | 2020 |
| Square Carbon Limited | Information & communication | 2013 |
| Square Health Group Limited | Information & communication | 2009 |
| Square Health Limited | Health & social care | 2009 |
| Square Health Technology Limited | Information & communication | 2021 |
| SRG Management Company Ltd | Households | 2020 |
| SS Educational Services Ltd | Education | 2019 |
| Ss&Ak Limited | Administrative & support | 2018 |
| SS22 Limited | Professional & scientific | 2019 |
| SSM Ventures Ltd | Real estate | 2025 |
| ST Anne's Mews Management Company Limited | Households | 2018 |
| ST Annes Property Holdings Limited | Real estate | 2019 |
| ST David's Cardiff Hotel Opco Limited | Hospitality | 2018 |
| ST George's House Trust (Windsor Castle) | Education | 1998 |
| ST Hanson Homes Limited | Construction | 2004 |
| ST Leonards House Residents Management Company Limited | Households | 2015 |
| ST Leonards OFF Licence Ltd | Wholesale & retail | 2025 |
| ST. Augustines (Westgate) Management Limited | Households | 2005 |
| ST. George's School Windsor Castle | Education | 2002 |
| ST. Johns Close (Uxbridge) Residents Association Limited | Households | 1982 |
| ST. Laurence Way Management Co. Limited | Households | 2001 |
| Stack Project Management Ltd | Professional & scientific | 2021 |
| Stackd Training Ltd | Other services | 2023 |
| Stackla Limited | Information & communication | 2014 |
| Staff Hub Recruitment Ltd | Administrative & support | 2025 |
| Stafford Boase Limited | Professional & scientific | 2012 |
| Stafford Developments Limited | Construction | 2012 |
| Stalwart Luxury Limited | Financial services | 2020 |
| Stan Thomas Limited | | 1958 |
| Stanbury Management Limited | Professional & scientific | 2023 |
| Starfish L&D Ltd | Administrative & support | 2016 |