| ROB Morton Consulting Ltd | Professional & scientific | 2024 |
| ROC Technologies Limited | Information & communication | 2011 |
| ROC Transformation (Corporate) Limited | Information & communication | 2017 |
| ROC Transformation (Group) Limited | Information & communication | 2017 |
| ROC Transformation (Holdings) Limited | Information & communication | 2017 |
| Rock Building Services Group Ltd | Manufacturing | 2000 |
| Rock IT Group Ltd | Information & communication | 1995 |
| Rofema Healthcare Ltd | Health & social care | 2014 |
| Rokstar Holdings Limited | Manufacturing | 2025 |
| Rose Gold Marketing Agency Ltd | Information & communication | 2012 |
| Rose Music Solutions Ltd | Information & communication | 2022 |
| Rosemary Bandini Limited | Wholesale & retail | 2013 |
| Rosier Physio & Movement Studio Limited | Health & social care | 2017 |
| Round House Consulting Limited | Administrative & support | 2020 |
| Royale Building Solutions Ltd | Construction | 2025 |
| Royale Decorators Ltd | Construction | 2024 |
| Rudland Close Ltd | Real estate | 2019 |
| Rudo Healthcare Solutions Ltd | Health & social care | 2020 |
| Run Forest Running Company Limited | Arts & recreation | 2024 |
| Rutland Consultancy (Berkshire) Ltd | Health & social care | 2021 |
| Ryan Salmon Consulting Limited | Professional & scientific | 2011 |
| Rylo Decorators Limited | Construction | 2018 |
| S D D Offshore Services Ltd | Energy | 2020 |
| S King Legal Ltd | Professional & scientific | 2025 |
| S T T Comms Limited | Information & communication | 2013 |
| S&D Sales Services Ltd | Wholesale & retail | 2024 |
| S&K Ventures Ltd | Wholesale & retail | 2022 |
| S&P Construction Services Ltd | Manufacturing | 2016 |
| SA Electrical Solutions Limited | Construction | 2025 |
| SA Global Technologies Limited | Information & communication | 2013 |
| SA Realtors Limited | Real estate | 2017 |
| Sabanci Limited | Professional & scientific | 1990 |
| Safe Estates Ltd | Real estate | 2022 |
| Safe Sanctuary Homes | Health & social care | 2020 |
| Sakura Advisory & Consulting Ltd | Information & communication | 2024 |
| Salmon Robotics Limited | Administrative & support | 2017 |
| Sapele Ltd | Administrative & support | 2015 |
| Saray Limited | Other services | 1998 |
| Sarcul Consulting Limited | Professional & scientific | 2014 |
| Sarcul Property Limited | Real estate | 2017 |
| Sarel Van Vuuren Limited | Health & social care | 2007 |
| Saronix B.V. | | 1998 |
| Saxon Court RTM Company Ltd | Households | 2016 |
| Saxon Treasury Ltd | Real estate | 2021 |
| SBT Electrical & Building Service Ltd | Construction | 2026 |
| SC4 Carpenters Limited | Construction | 2000 |
| SC4 Decorators Limited | Construction | 2007 |
| Schiltron Equine Ltd | Agriculture & fishing | 2020 |
| Scion Communications Fire & Security Ltd | Administrative & support | 2020 |
| Scion Communications Limited | Information & communication | 2002 |
| Scion Tech Limited | Manufacturing | 2012 |
| Scod Consulting Ltd | Professional & scientific | 2012 |
| Script and DOT Ltd | Administrative & support | 2019 |
| Seajourney Ltd | Information & communication | 2026 |
| Sealink Inspection Limited | Professional & scientific | 2021 |
| Second Truck Ltd | Transport & logistics | 2015 |
| Securicall Systems Limited | Administrative & support | 2010 |
| Sedap Sauces Ltd | Manufacturing | 2025 |
| Sense Labs International Ltd | Information & communication | 2020 |
| September Engineering Limited | Professional & scientific | 2017 |
| Serenity Aesthetics & Skincare Ltd | Other services | 2025 |
| Sergio Afro-Caribbean Cuisine Limited | Hospitality | 2023 |
| Serqa Limited | Administrative & support | 2012 |
| Serravalle Limited | Construction | 2020 |
| Setpoint Compliance Limited | Professional & scientific | 2026 |
| Sgmn Consultants Limited | Professional & scientific | 2012 |
| SGO UK Limited | Information & communication | 2009 |
| Shafer Estates Limited | Construction | 2000 |
| Sharada Properties Management Services Limited | Real estate | 2026 |
| Sharps Drain Logic Limited | Construction | 1992 |
| Sharps Drainage Services Limited | Construction | 1999 |
| SHC International Limited | Professional & scientific | 2017 |
| Shelby’S Sparkle Squad Ltd | Administrative & support | 2024 |
| Shepherd Franks Ltd | Professional & scientific | 2020 |
| Shlok Consulting Limited | Information & communication | 2011 |
| Shlok Enterprises Limited | Wholesale & retail | 2011 |
| Shoo 677 Limited | Financial services | 2023 |
| Shoreline Yacht Transport Limited | Transport & logistics | 2002 |
| SHP Property Solutions Ltd | Real estate | 2017 |
| Shravi Limited | Information & communication | 2018 |
| Si-Bone UK Ltd | Wholesale & retail | 2015 |
| Siam Ocean Technologies Limited | Construction | 2019 |
| Sian Abel Consulting Limited | Administrative & support | 2022 |
| Sicaco Ltd | Professional & scientific | 2018 |
| Signrite Digital Limited | Manufacturing | 2018 |
| Silent Deer Limited | Other services | 2009 |
| Silva Cabs Ltd | Other services | 2024 |
| Silver Birch Leadership Ltd | Professional & scientific | 2023 |
| Silver Laughter Limited | Education | 2007 |
| Silverberry Limited | Other services | 2003 |
| Simetrix Technologies Ltd. | Information & communication | 1987 |
| Simon Hannam Limited | Administrative & support | 2008 |
| Simply Copy Co Ltd | Professional & scientific | 2024 |
| Simply Oak Ltd | Construction | 2015 |
| Simpson Software & Security Ltd | Information & communication | 2022 |
| Sipa Honey Bees Limited | Agriculture & fishing | 2023 |
| Sirvis IT Holdings Limited | Information & communication | 2008 |
| Sirvis IT Limited | Information & communication | 1996 |
| Siskin House Ltd | Professional & scientific | 2022 |
| SJD Property (Reading) Ltd | Real estate | 2021 |