| Suhaan Healthcare Limited | Health & social care | 2024 |
| Sulaj Properties Ltd | Real estate | 2024 |
| Sultan House RTM Company Limited | Households | 2022 |
| Summer Dreams Holidays Limited | Administrative & support | 2021 |
| SUMMIT24 Strategies Ltd | Professional & scientific | 2025 |
| Sumz Dog Grooming Limited | Other services | 2024 |
| Sun Exotic Wholesale Ltd | Wholesale & retail | 2013 |
| Sun Shine Ventures Ltd | Real estate | 2024 |
| Suncrop Generation Limited | Agriculture & fishing | 2023 |
| Suncrop Growers Limited | Agriculture & fishing | 2017 |
| Suncrop Produce Limited | Wholesale & retail | 1996 |
| Sundara Salon Ltd | Other services | 2022 |
| Sundridge Court Residents Association Limited | Households | 1996 |
| Sundridge Park Mansion Residents Company Limited | Households | 2018 |
| Sundry Agro Ltd | Wholesale & retail | 2022 |
| Suni Trans Ltd | Transport & logistics | 2016 |
| Sunna Properties Ltd | Real estate | 2022 |
| Sunrise Private Care Limited | Health & social care | 2020 |
| Sunrise Support Services Ltd | Hospitality | 2025 |
| Sunrise Transitional Services Limited | Health & social care | 2015 |
| Sunset (Woodford Green) Management Company Limited | Households | 1977 |
| Suntek UK Limited | Wholesale & retail | 2009 |
| Super Sky Limited | Professional & scientific | 1986 |
| Supercar Detailing Limited | Professional & scientific | 2003 |
| Superfest Limited | Administrative & support | 2023 |
| Superstar Group Limited | Health & social care | 2025 |
| Supofood Ltd | Wholesale & retail | 2026 |
| Supply Twelve Limited | Administrative & support | 2022 |
| Supplyguy Limited | Wholesale & retail | 2026 |
| Supplynx Ltd | Wholesale & retail | 2025 |
| Supported Living Invest Limited | Real estate | 2025 |
| Sure Scaffolding Ltd | Construction | 2016 |
| Surehomes Property Limited | Real estate | 2024 |
| Surgery Social Ltd | Health & social care | 2025 |
| Surka Limited | Hospitality | 2019 |
| Susan Higgs Creative Ltd | Wholesale & retail | 2017 |
| Sushisupplier Ltd | Wholesale & retail | 2026 |
| Sussex Speech Studio Ltd | Health & social care | 2023 |
| Suzi Merchant Ltd | Wholesale & retail | 2025 |
| Suzyo Limited | Health & social care | 2019 |
| SVN Services Limited | Manufacturing | 2014 |
| Svown Ltd | Financial services | 2016 |
| SW Contracting Ltd | Information & communication | 2025 |
| Swabokun Enterprises Ltd | Transport & logistics | 2025 |
| Swaf Adornments Ltd | Professional & scientific | 2018 |
| Swan Forklift Training Limited | Administrative & support | 2015 |
| Swann Transport Ltd | Transport & logistics | 2025 |
| Swat Enterprise Limited | Manufacturing | 2016 |
| Swathy Limited | Health & social care | 2020 |
| Swatkins Company Ltd | Professional & scientific | 2024 |
| Sweet Balay Limited | Real estate | 2024 |
| Sweet Cake 4 YOU Limited | Hospitality | 2021 |
| Sweet Footwear Limited | Wholesale & retail | 2013 |
| Sweet Footwear London Limited | Wholesale & retail | 2014 |
| Sweetite Limited | Information & communication | 2021 |
| Sweetreds Limited | Administrative & support | 2019 |
| Swift FIX Maintenance Ltd | Construction | 2023 |
| Swift Logic Medical Services Limited | Health & social care | 2023 |
| Swift Mobile Accountant Ltd | Professional & scientific | 2018 |
| Swift Speed Ltd | Professional & scientific | 2026 |
| Swiftech Consulting Limited | Information & communication | 2017 |
| Swifttip Global Ltd | Transport & logistics | 2025 |
| Swiftwings Freight Ltd | Transport & logistics | 2026 |
| Swim Fast Ltd | Wholesale & retail | 2026 |
| Switchnet Systems Limited | Information & communication | 1996 |
| Swon Concept Limited | Administrative & support | 2011 |
| Swon Education Limited | Education | 2024 |
| Swon Property Investment Ltd | Real estate | 2022 |
| Swph Ltd | Construction | 2010 |
| SWR Motorsport Limited | Arts & recreation | 2000 |
| Sybron (Holdings) Limited | Financial services | 2024 |
| Sybron (UK) Limited | Wholesale & retail | 2002 |
| Sycametry Telehealth Ltd | Professional & scientific | 2012 |
| Sycamore Blue Care Services Ltd | Public administration | 2025 |
| Sycamore Care Service Ltd | Health & social care | 2016 |
| Sycamore Inc Limited | Real estate | 2026 |
| Syeda Zainab Trust | Education | 2009 |
| Sylvester Roofing Ltd | Construction | 2024 |
| Sylvia Nwokolo Limited | Health & social care | 2020 |
| Symphony Change Management Solutions Ltd | Information & communication | 2008 |
| Synero Limited | Wholesale & retail | 2023 |
| Synna Limited | Wholesale & retail | 2025 |
| Syntex Medicare Consult Ltd | Health & social care | 2024 |
| Synthomer (UK) Limited | Manufacturing | 1966 |
| Synthomer Adhesive Technology Limited | Financial services | 2022 |
| Synthomer Holdings Limited | Professional & scientific | 2002 |
| Synthomer Trading Limited | Manufacturing | 2016 |
| System Innovators(Gb) Ltd | Information & communication | 2012 |
| System Labs Limited | Information & communication | 2002 |
| Systemag Ltd | Education | 2025 |
| Systems and Scale Group Ltd | Information & communication | 2026 |
| Szymanski Car Services Ltd | Wholesale & retail | 2016 |
| Szymonbudrze Ltd | Water & waste | 2023 |
| T & a Comfort African Food Ltd | Wholesale & retail | 2026 |
| T & B Unisex Beauty Salon Ltd | Other services | 2024 |
| T & O Consultancy Limited | Health & social care | 2022 |
| T & T Medical Limited | Health & social care | 2019 |
| T Hawks Limited | Construction | 2012 |
| T S Arable LLP | | 2006 |
| T S Electronics Limited | Information & communication | 1990 |