| SK & Daughters Ltd | Financial services | 2019 |
| SK Innovative Solutions Ltd | Information & communication | 2024 |
| SK PRE Schools Ltd | Health & social care | 2021 |
| Skaf Ltd | Other services | 2002 |
| Skan Homes Limited | Real estate | 2017 |
| SKD Construction Ltd | Construction | 2022 |
| Skeet Limited | Professional & scientific | 2016 |
| Skew Studios Ltd | Information & communication | 2016 |
| Skills Growth Chelmsford Limited | Education | 2022 |
| Skills Growth Croydon Limited | Education | 2022 |
| Skills Growth Group Limited | Education | 2022 |
| Skills Growth Ipswich Limited | Education | 2022 |
| Skills Growth London Limited | Education | 2022 |
| Skillscrafter Limited | Education | 2025 |
| Skim, Slice & CUT Limited | Extraterritorial | 2021 |
| Skin Revolution Limited | Professional & scientific | 2016 |
| Skin Specialist Essex Limited | Health & social care | 2012 |
| Skinforia Limited | Wholesale & retail | 2016 |
| Skml Ltd | Information & communication | 2010 |
| SKN Installations Ltd | Administrative & support | 2022 |
| Skohf Homes Limited | Health & social care | 2020 |
| Skohf Investments Ltd | Real estate | 2018 |
| Skohf Properties Limited | Real estate | 2022 |
| Skrinch Ltd | Construction | 2023 |
| Skss Medical Management Ltd | Health & social care | 2023 |
| Skulpture Body & Mind Ltd | Other services | 2021 |
| Sky High Homes Limited | Real estate | 2023 |
| Sky Taverns Limited | Hospitality | 2016 |
| Skylark International Community | Other services | 2003 |
| Skylark Projects Limited | Professional & scientific | 2023 |
| Skyline Decorating Limited | Construction | 2020 |
| Skyn MED Spa Ltd | Other services | 2022 |
| Skyrae Ltd | Professional & scientific | 2023 |
| Skyspace Limited | Real estate | 2025 |
| SL Higgs Ltd | Administrative & support | 2026 |
| SL Records Ltd | Wholesale & retail | 2019 |
| SL27 Ltd | Wholesale & retail | 2020 |
| SL5 Ltd | Professional & scientific | 2014 |
| Slam Analytics Limited | Information & communication | 2016 |
| Slam Arch Ltd | Construction | 2024 |
| Slate Bern Consulting Limited | Professional & scientific | 2024 |
| Slave to the Vibe Limited | Arts & recreation | 2014 |
| SLC Marketing Limited | Professional & scientific | 2023 |
| Sled Healthcare Ltd | Health & social care | 2022 |
| Sleepytime Solutions Ltd | Construction | 2022 |
| Sles Contracts Ltd | Construction | 2021 |
| SLG Group Limited | Professional & scientific | 2024 |
| SLG Property Services Limited | Real estate | 2025 |
| Slice & Dough Ltd | Hospitality | 2026 |
| Slice, Skim & CUT Limited | Extraterritorial | 2021 |
| Slim Sam's Cakery Limited | Manufacturing | 2011 |
| Slinger Tomson Productions Ltd. | Arts & recreation | 1993 |
| Slings & Arrows Ltd | Professional & scientific | 2025 |
| Slipform Solutions Ltd | Construction | 2011 |
| SLJ Commercials Ltd | Wholesale & retail | 2021 |
| SLJ Group Limited | Professional & scientific | 2020 |
| SLL Investment Limited | Real estate | 2016 |
| SLP Autos Limited | Wholesale & retail | 2004 |
| Slscc Ltd | Arts & recreation | 2020 |
| SLV Financial Planning Limited | Professional & scientific | 2020 |
| SM Allen Properties Ltd | Real estate | 2021 |
| SM PR & Communications Ltd | Information & communication | 2017 |
| Small Steps Pre-School Boreham | Education | 2011 |
| Small Town Fuels Limited | Wholesale & retail | 2023 |
| Small Wonders Day Nurseries Ltd | Health & social care | 2012 |
| Smans Villas Ltd | Administrative & support | 2017 |
| Smart Accounting Solutions (London) Limited | Professional & scientific | 2011 |
| Smart Air Ltd | Professional & scientific | 2021 |
| Smart Automate Ltd | Construction | 2022 |
| Smart Business Management (UK) Limited | Information & communication | 2009 |
| Smart Digital TV Limited | Information & communication | 2014 |
| Smart Engineering and Design Ltd | Professional & scientific | 2022 |
| Smart FIX South East Limited | Construction | 2024 |
| Smart FIX Systems Limited | Construction | 2020 |
| Smart Lawn Solutions Ltd | Construction | 2025 |
| Smart Mortgage Professionals Limited | Financial services | 2017 |
| Smart Plus Properties Ltd | Real estate | 2023 |
| Smart Practice Management UK Ltd | Professional & scientific | 2013 |
| Smart Safety Solutions (Essex) Limited | Professional & scientific | 2025 |
| Smart Seniors Ltd | Information & communication | 2025 |
| Smart Tech Consultancy Ltd | Extraterritorial | 2012 |
| Smart Tiling Contractors Limited | Construction | 2010 |
| Smart Tools (UK) Ltd | Professional & scientific | 2003 |
| Smart Voie Ltd | Information & communication | 2024 |
| Smartcore Tech Limited | Information & communication | 2026 |
| Smartlodge Property Group Limited | Financial services | 2020 |
| Smartmove COD Limited | Real estate | 2025 |
| Smartseal Property Investments Ltd | Real estate | 2021 |
| Smartseal UK Ltd | Wholesale & retail | 2008 |
| Smartyn Limited | Real estate | 2025 |
| Smashing Buns Ltd | Hospitality | 2014 |
| SME Mechanical & Electrical Ltd | Construction | 2011 |
| Smeckleywood Management Limited | Financial services | 2015 |
| Smelly Feet Solutions Limited | Health & social care | 2025 |
| SMF Traders Limited | Wholesale & retail | 2024 |
| Smgwa Trading Limited | Other services | 2015 |
| Smile HQ Limited | Health & social care | 2022 |
| Smiles by Gaya Ltd | Health & social care | 2025 |
| Smillie Scaffolding Services Ltd | Construction | 2019 |
| Smith Asset Properties Ltd | Real estate | 2021 |