| Solarponics UK Limited | Agriculture & fishing | 2016 |
| Solca Building Ltd | Construction | 2025 |
| Solicitas Associates Limited | Financial services | 2015 |
| Solid Brick Ltd | Real estate | 2023 |
| Solid Talent Limited | Administrative & support | 2025 |
| Solo Ace Ltd | Construction | 2024 |
| SOLO60 Ltd | Arts & recreation | 2019 |
| Solutions TAD Limited | Construction | 2009 |
| Solvex Consulting Limited | Administrative & support | 2018 |
| Somani Hotels (ST Albans) Ltd | Hospitality | 2023 |
| Sonacode Ltd | Information & communication | 2019 |
| Soni Prints Limited | Manufacturing | 2025 |
| Sonic Baume Ltd | Information & communication | 2022 |
| Sonita's Kitchen Limited | Hospitality | 2007 |
| Sontech Consulting Ltd | Information & communication | 2022 |
| Sontinium Ltd | Wholesale & retail | 2025 |
| Sophisticare Ltd | Health & social care | 2025 |
| Sort and Declutter Ltd. | Households | 2017 |
| Soul Beauty & Hair Ltd | Other services | 2025 |
| Soultaker Fightwear Ltd | Wholesale & retail | 2026 |
| Sound Asleep Guru Limited | Other services | 2026 |
| Sound Property Investment Limited | Real estate | 2016 |
| Soundsfun Studio Ltd | Manufacturing | 2023 |
| Soundtrip Limited | Information & communication | 2026 |
| Source Black Automotive Limited | Wholesale & retail | 2026 |
| Sourcing Sustainably Limited | Professional & scientific | 2014 |
| South East Sterilisers Limited | Administrative & support | 2012 |
| South Eastern Leisure UK Limited | Construction | 1998 |
| South Riding Limited | Hospitality | 2025 |
| Southampton Cleaning Services Ltd | Administrative & support | 2025 |
| Southview Property Holdings Ltd | Real estate | 2016 |
| Southwell Site Services Ltd | Construction | 2017 |
| Sovereign Chauffeur Ltd | Transport & logistics | 2026 |
| Sovereign Recovery (UK) Limited | Wholesale & retail | 2006 |
| Sovereign Recovery Limited | Transport & logistics | 2008 |
| Sovereign Recovery Specialists Limited | Wholesale & retail | 2010 |
| Sovereign Recruitment Solutions Ltd | Administrative & support | 2011 |
| SP Wealth Management Limited | Financial services | 2012 |
| Space to BE Therapy Ltd | Health & social care | 2025 |
| Spacex Opportunity 1 LP | | 2025 |
| Spark IT Ltd | Information & communication | 2006 |
| Sparkes Technology Consulting Ltd | Professional & scientific | 2025 |
| Sparkle Bright Home Services Ltd | Administrative & support | 2019 |
| Sparktech SPV AF1 LLP | | 2021 |
| Sparky Ltd | Information & communication | 2026 |
| Sparrow Hill Properties Ltd | Real estate | 2016 |
| Spartan Heating Engineers Limited | Construction | 2021 |
| SPD Data Consulting Ltd | Information & communication | 2025 |
| Speak Communications Limited | Administrative & support | 2009 |
| Speakto Limited | Professional & scientific | 2012 |
| Spearhall Developers Ltd | Administrative & support | 2007 |
| Specialised Research (UK) Limited | Financial services | 2012 |
| Specialist Autos Limited | Wholesale & retail | 2024 |
| Specialist Electrical Solutions Ltd | Construction | 2024 |
| Specialist Hygienist Services Ltd | Health & social care | 2025 |
| Specialist Plastercraft Limited | Construction | 2003 |
| Specialist Renovations Developments Limited | Construction | 2010 |
| Specialists in Sports Architecture (Sisa) Ltd | Professional & scientific | 2023 |
| Specialty Diagnostix GB & NI Limited | Wholesale & retail | 2025 |
| Speckled Bird Fellowship CIC | Other services | 2018 |
| Spectra Construction Ltd | Construction | 2019 |
| Spectrum Neurocare Community Interest Company | Education | 2026 |
| Speculate Construction Limited | Construction | 2025 |
| Speed 9236 Limited | Construction | 2002 |
| Speedbroker Ltd | Other services | 2020 |
| Speirs Consulting Services Limited | Professional & scientific | 2020 |
| Spezific Consulting Limited | Information & communication | 2015 |
| Sphere Data Protection Limited | Extraterritorial | 2018 |
| Sphere HR Ltd | Administrative & support | 2013 |
| SPI Spirits (UK) Limited | Professional & scientific | 2002 |
| Spice Traders of Daventry Ltd | Hospitality | 2025 |
| Spigz Riggz Ltd | Information & communication | 2019 |
| Spinola Group Ltd | Real estate | 2017 |
| Spire Bricks and Mortar Limited | Real estate | 2015 |
| Spirit Holdings Limited | Real estate | 2015 |
| Splash Insight Limited | Professional & scientific | 2018 |
| Splendid Money Ltd | Financial services | 2025 |
| Splendiferous Events Limited | Hospitality | 2015 |
| Spoke BIO Ltd | Information & communication | 2024 |
| Spoko Handyman Ltd | Construction | 2021 |
| Sponsar Limited | Information & communication | 2023 |
| Sporting Index Limited | Arts & recreation | 1991 |
| SPORTS248 Ltd | Wholesale & retail | 2020 |
| Spot Ship Exchange Holdings Ltd | Wholesale & retail | 2019 |
| Spotless Cleaner Lady Ltd | Administrative & support | 2025 |
| Spreadex Limited | Arts & recreation | 1999 |
| Spreadex.Com Limited | Arts & recreation | 1998 |
| Spring Logistics (UK) Limited | Transport & logistics | 2017 |
| Spry Consulting Ltd | Information & communication | 2010 |
| Spud Contract Services Limited | Administrative & support | 2020 |
| Spudling Ltd | Professional & scientific | 2023 |
| SQ Cricket Ltd | Manufacturing | 2025 |
| Squared Homes Ltd | Construction | 2021 |
| SRB Civil Engineering UK Limited | Construction | 2010 |
| SRI Narasimha Ltd | Health & social care | 2023 |
| Srjc Properties Limited | Real estate | 2017 |
| SRS Advisory Ltd | Professional & scientific | 2024 |
| SRT Controls Ltd | Information & communication | 2013 |
| SS Billing Consultants Limited | Information & communication | 2017 |
| SSA Management Company Ltd | Households | 2011 |