| Sonu Builders Ltd | Construction | 2023 |
| Soor Homes Ltd | Real estate | 2020 |
| Sooyaal Limited | Transport & logistics | 2019 |
| Sophiaworld Ltd | Education | 2015 |
| Sophie Gardens Management Limited | Other services | 2003 |
| Sophieandi Ltd | Arts & recreation | 2024 |
| Sophisticated Living Ltd | Real estate | 2026 |
| Sorbe Events and Catering Limited | Hospitality | 2026 |
| Sorelle Investments Limited | Real estate | 2008 |
| Sorescu Ltd | Transport & logistics | 2016 |
| Sorrento Takeaway Ltd | Hospitality | 2025 |
| Sort Hub Ltd | Transport & logistics | 2025 |
| Sort Style and Stage Limited | Construction | 2019 |
| Sorted Tyres Ltd | Wholesale & retail | 2023 |
| Sospel Management Co Ltd | Households | 2013 |
| Sota Systems Limited | Information & communication | 1997 |
| Soteria Supported Housing CIC | Hospitality | 2021 |
| SOU Group Ltd | Construction | 2025 |
| Soubise UK Limited | Real estate | 2023 |
| Soul Clean Ltd | Administrative & support | 2010 |
| Soul Logistics Limited | Wholesale & retail | 2024 |
| Soulful Collection Limited | Professional & scientific | 2009 |
| Soulworks Counselling Limited | Health & social care | 2018 |
| Soundmindsuk Ltd | Education | 2020 |
| Source Electrical Supplies Limited | Wholesale & retail | 2012 |
| Source Marketing Ltd | Administrative & support | 2025 |
| SOURCE4BITS Ltd | Wholesale & retail | 2022 |
| South Bucks Bridge Club | Arts & recreation | 2016 |
| South East England Faiths Forum | Other services | 2010 |
| South Green Energy Ltd | Construction | 2022 |
| South Lincs Foodservice Limited | Wholesale & retail | 1981 |
| South Quay Residential Ltd | Real estate | 2022 |
| South Surrey Gardens Ltd | Administrative & support | 2025 |
| Southall Bargain Furniture Limited | Wholesale & retail | 2015 |
| Southall Flower Land Ltd | Wholesale & retail | 2026 |
| Southend Investments Limited | Real estate | 2025 |
| Southern Facility Services Ltd | Construction | 2012 |
| Southern Installations Limited | Manufacturing | 2025 |
| Southern Star (SA) Limited | Construction | 2015 |
| Sovereign FM Ltd | Construction | 1997 |
| Sovereign Panjab Ltd | Transport & logistics | 2019 |
| Sovereign Speed (UK) Limited | Transport & logistics | 2003 |
| Sovich Ltd | Arts & recreation | 2014 |
| Sovrin Ltd | Manufacturing | 2009 |
| Sovrin Medical Ltd | Manufacturing | 2009 |
| Sovrin Plastics Limited | Manufacturing | 1969 |
| Sowjanya IT Services Ltd | Information & communication | 2012 |
| SP the Estate Management Ltd | Real estate | 2015 |
| SP UK Construction Ltd | Construction | 2026 |
| SP UK Global Ltd | Information & communication | 2024 |
| Spa Property Services Limited | Construction | 2026 |
| Spa Real Estate Limited | Real estate | 2019 |
| Spaag Traders Ltd | Wholesale & retail | 2025 |
| Space Black CIC | Professional & scientific | 2023 |
| Space Cat Trading Ltd | Wholesale & retail | 2019 |
| Space Glow Ltd | Wholesale & retail | 2018 |
| Space in London Limited | Real estate | 2000 |
| Space Infra Ltd | Real estate | 2024 |
| Space Property 0 Ltd | Construction | 2023 |
| Space Property 1 Ltd | Real estate | 2022 |
| Space Property 2 Ltd | Construction | 2022 |
| Space Property 3 Ltd | Construction | 2024 |
| Spaces Property Agents Limited | Real estate | 2026 |
| Spacia Systems Limited | Other services | 2016 |
| Spal Services Ltd | Construction | 2023 |
| Spark & Shine Services Ltd | Administrative & support | 2025 |
| Spark Pro Cleaning Services Ltd | Administrative & support | 2025 |
| Spark Share Limited | Other services | 2022 |
| Spark UP Your Light Ltd | Education | 2025 |
| Sparkle Squad Ltd | Administrative & support | 2024 |
| Sparkle Star London Ltd | Construction | 2022 |
| Sparks Drivers Ltd | Transport & logistics | 2020 |
| Sparksure Cleaning Ltd | Administrative & support | 2025 |
| Spartathree Limited | Extraterritorial | 2025 |
| Sparthill Property LLP | | 2016 |
| Sparxsys Properties Limited | Real estate | 2024 |
| Sparxsys Solutions Limited | Information & communication | 2019 |
| SPB Corporation Limited | Information & communication | 2015 |
| Speak IT BE IT Limited | Manufacturing | 2018 |
| Spear Logistics Ltd | Transport & logistics | 2012 |
| Spec Diver Ltd | Professional & scientific | 2024 |
| Special Air Travel Ltd | Administrative & support | 2012 |
| Spectra Techs Limited | Information & communication | 2017 |
| Spectraaz Ltd | Transport & logistics | 2026 |
| Spectrum Cargo Services Limited | Transport & logistics | 1996 |
| Spectrum Consultant Limited | Real estate | 1999 |
| Speech Hoppy Ltd | Health & social care | 2023 |
| Speed Plumbing Ltd | Construction | 2024 |
| Speedbird Software Ltd | Information & communication | 2021 |
| Speedmain Contractors Ltd | Construction | 2013 |
| Speedman UK Ltd | Real estate | 2013 |
| Speedmax Global Ltd | Information & communication | 2024 |
| Speedway Enterprises Ltd | Information & communication | 2021 |
| Speedy Cleaners Berkshire Ltd | Administrative & support | 2022 |
| Speedy Sloth Ltd | Wholesale & retail | 2026 |
| Speedylowcost Ltd | Wholesale & retail | 2021 |
| Speedymotorspace Ltd | Wholesale & retail | 2024 |
| Speedynetworks Ltd | Information & communication | 2025 |
| Spegel Ltd | Real estate | 2024 |
| Spellbound Technologies Limited | Information & communication | 2024 |