| Smell the Coffee Communications Limited | Professional & scientific | 2024 |
| Smether Limited | Health & social care | 2023 |
| Smile Makeover Dental Laboratory Ltd | Health & social care | 2026 |
| Smiles by JEZ Limited | Health & social care | 2022 |
| Smileville Orthodontics Limited | Health & social care | 2018 |
| Smiley Builders Ltd | Construction | 2024 |
| Smine Ltd | Wholesale & retail | 2026 |
| Smith and Cosgrove Limited | Real estate | 2023 |
| SMJ Medical Ltd | Health & social care | 2016 |
| SML UK Services Ltd | Construction | 2018 |
| Smokyy EGG Limited | Hospitality | 2023 |
| SMP Building & Construction Ltd | Construction | 2026 |
| Snap Cars Ltd | Transport & logistics | 2023 |
| Snap Deck Collectables Ltd | Wholesale & retail | 2024 |
| Snap Merchandising Limited | Professional & scientific | 2015 |
| Sniff Sniff Zoom! Ltd | Arts & recreation | 2026 |
| Snkt Ltd | Wholesale & retail | 2025 |
| Snootie Studios Limited | Arts & recreation | 2018 |
| SNS PVT Ltd | Wholesale & retail | 2016 |
| Soapstone Global Limited | Wholesale & retail | 2025 |
| Social Extract AI Ltd. | Administrative & support | 2021 |
| Socialb.Management Ltd | Manufacturing | 2024 |
| Socius Global Sourcing Limited | Wholesale & retail | 2016 |
| Sofon UK Limited | Information & communication | 2007 |
| Soft Touches Aesthetics Ltd | Health & social care | 2021 |
| Softtech Limited | Administrative & support | 2008 |
| Soge-Higgs Limited | Health & social care | 2023 |
| Sohail Ahmad Ltd | Wholesale & retail | 2025 |
| Sohan Properties Ltd | Real estate | 2022 |
| Sohno Ltd | Wholesale & retail | 2026 |
| Sokoli Construction Ltd | Construction | 2019 |
| Sokoli Property Ltd | Real estate | 2023 |
| SOL Health Ltd | Health & social care | 2024 |
| SOL Services (Yorkshire) Ltd | Construction | 2016 |
| Solar Central Limited | Construction | 2019 |
| Solarbeta Management Company Limited | Households | 2006 |
| Solbat Spotless Cleaning Ltd | Administrative & support | 2026 |
| Solid Carpentry Solutions Ltd | Construction | 2019 |
| Solo Electronic Services Ltd | Manufacturing | 2024 |
| Solobotagency Limited | Information & communication | 2023 |
| Solstice Strategies Limited | Professional & scientific | 2025 |
| Solvito Ltd | Administrative & support | 2026 |
| Solviva Care Ltd | Health & social care | 2026 |
| Solvnext Limited | Administrative & support | 2024 |
| SOM Healthcare Limited | Public administration | 2023 |
| Somak International Limited | Wholesale & retail | 2025 |
| Somerset Gardens Management Co. Limited | Households | 1990 |
| Somnien Limited | Administrative & support | 2021 |
| SON of Peter Ventures Limited | Real estate | 2025 |
| SON Sabores Limited | Transport & logistics | 2018 |
| Sona Safar Ltd | Wholesale & retail | 2022 |
| Sonaa Medical Limited | Health & social care | 2026 |
| Soni Enterprises Ltd | Hospitality | 2017 |
| Sonny Motorsports Ltd | Other services | 2025 |
| Sonoecho Ltd | Health & social care | 2026 |
| Sonolite Limited | Manufacturing | 2021 |
| Sontag & Sons Plumbing Ltd | Construction | 2020 |
| Sood Commercial Ltd | Real estate | 2025 |
| Soolar Concepts Limited | Wholesale & retail | 2017 |
| Soothing Strokes Therapies Limited | Health & social care | 2018 |
| SOP International Limited | Manufacturing | 1984 |
| Sophie DO Healthcare Ltd | Health & social care | 2025 |
| Sophie Hall Limited | Wholesale & retail | 2011 |
| Sora RYU Ltd | Information & communication | 2023 |
| SOS Hotel Solutions Limited | Professional & scientific | 2013 |
| Soul Sync Spiritual Ltd | Health & social care | 2026 |
| SOUL2SPICE Limited | Hospitality | 2020 |
| Souldii Care Ltd | Health & social care | 2019 |
| Soulfex Limited | Wholesale & retail | 2025 |
| Sound-To-Go Ltd | Wholesale & retail | 2003 |
| Source Facilities Maintenance Limited | Construction | 2015 |
| Sourial Consultancy Ltd | Information & communication | 2019 |
| South Bay Homes Ltd | Real estate | 2025 |
| South East Counties Electrical Services Ltd | Construction | 2018 |
| South East Harlow Sports & Youth Association | Hospitality | 2002 |
| South Essex Automotive Accessories Limited | Wholesale & retail | 2014 |
| South ROW Residents' Society Limited | Households | 1985 |
| South Side Farm (Corston) Management Company Limited | Households | 2017 |
| South View Heights Management Company Limited | Households | 1999 |
| Southend Farm (Upshire) Ltd | Real estate | 2024 |
| Southern Property Management Service Ltd | Real estate | 2017 |
| Southgate Way RTM Company Limited | Households | 2011 |
| Southstep Ltd | Information & communication | 1996 |
| Souza Lettings Ltd | Real estate | 2026 |
| Souza Transport Ltd | Transport & logistics | 2020 |
| Sovereignty Care Ltd | Health & social care | 2018 |
| Sozo Medical Ltd | Administrative & support | 2020 |
| SP Conveyancing Consultants Ltd | Professional & scientific | 2026 |
| SP Fusion UK Limited | Professional & scientific | 2025 |
| SP8 Construction Ltd | Construction | 2019 |
| Space Trace Ltd | Information & communication | 2021 |
| Spacontractors Ltd | Manufacturing | 2019 |
| Spak Consulting Ltd | Information & communication | 2023 |
| Sparebox Ltd | Wholesale & retail | 2025 |
| Sparker Ltd | Wholesale & retail | 2026 |
| Sparkl COMFORT1 Limited | Real estate | 2026 |
| Sparkle Car Wash Ltd | Construction | 2025 |
| Sparkle Professional Cleaning Services Ltd | Administrative & support | 2026 |
| Sparkling Smiles by Rina Ltd | Health & social care | 2024 |
| Sparlings Farm Management Ltd | Households | 2025 |