| Steel Nexus Ltd | Manufacturing | 2016 |
| Stefantonchev Ltd | Manufacturing | 2023 |
| Stefantransport Limited | Transport & logistics | 2025 |
| Stefid Ltd | Health & social care | 2019 |
| Sterling Property Rentals Ltd | Real estate | 2026 |
| Steve Good Builder Ltd | Construction | 2026 |
| Steve Hodgson Services Limited | Construction | 2016 |
| Steve Skinner CBT Ltd | Health & social care | 2024 |
| Steve's Home Improvements Ltd | Manufacturing | 2025 |
| Stewart Annetts Building Maintenance Ltd | Households | 2024 |
| Stickney MOT Center Ltd | Wholesale & retail | 2023 |
| Stickylabels Limited | Manufacturing | 2005 |
| Stilinga Krautuvele UK Ltd | Wholesale & retail | 2024 |
| Stockholm Investering Limited | Construction | 2024 |
| Stonetreat Limited | Real estate | 1987 |
| Storage Floor Installers Ltd | Manufacturing | 2020 |
| Strategic Vehicle Solutions Ltd | Wholesale & retail | 2023 |
| Strategy Electrical Limited | Construction | 2024 |
| Strategy Living Services Limited | Real estate | 2025 |
| Streamline Pizza Company Limited | Hospitality | 2012 |
| Streetfox Motors Ltd | Wholesale & retail | 2026 |
| Stressless Dental Care Ltd. | Health & social care | 2013 |
| Stridemax Limited | Manufacturing | 2025 |
| Stripe Agriculture Limited | Wholesale & retail | 2012 |
| Studio 11 Clifton Ltd | Other services | 2024 |
| Studio 21 Design Ltd | Professional & scientific | 2013 |
| Studio 360 Boston Ltd | Other services | 2024 |
| Studio TEN (Johnsons) Ltd | Other services | 2020 |
| Studio TEN Limited | Other services | 2006 |
| Stukeley Holdings Limited | Real estate | 2020 |
| Stukeley Properties Limited | Real estate | 2003 |
| Stump Properties Limited | Real estate | 2015 |
| STV Construct Ltd | Construction | 2024 |
| Stydex Limited | Professional & scientific | 2004 |
| Suave Panda Ltd | Real estate | 2022 |
| Subhan Events Management UK Ltd | Wholesale & retail | 2025 |
| Sublimity Bathrooms Ltd | Other services | 2015 |
| Sundown Productions Ltd | Professional & scientific | 2025 |
| Superior Pet Products Limited | Professional & scientific | 2001 |
| Superior Roofing & Development Limited | Construction | 2026 |
| Supplies & Services (Nottingham) Limited | Real estate | 1964 |
| Supply BIO Logistics Ltd | Agriculture & fishing | 2026 |
| Supreme (Events) Hotel Limited | Hospitality | 2010 |
| Supreme Properties Lincs Ltd | Real estate | 2013 |
| Supreme Public House Limited | Hospitality | 2010 |
| Surelocked Homes Ltd | Manufacturing | 2026 |
| Surfaceworks Boston Ltd | Wholesale & retail | 2025 |
| Sushi Crush Limited | Hospitality | 2025 |
| Susmara Limited | Transport & logistics | 2019 |
| Sussex Marine Supplies Limited | Wholesale & retail | 2024 |
| Sutterton Label Printers Limited | Financial services | 1979 |
| Suttons Farms Limited | Agriculture & fishing | 1970 |
| SVK Fabs Ltd | Manufacturing | 2026 |
| Svyturys Limited | Hospitality | 2018 |
| Swandyke Farm Limited | Hospitality | 2024 |
| Sweet Angels Childminding Limited | Health & social care | 2022 |
| Sweeter Things Limited | Wholesale & retail | 2022 |
| Sweetmans Interiors Limited | Manufacturing | 2016 |
| Swift Employment Ltd | Administrative & support | 2021 |
| Swiftly Move Properties Ltd | Real estate | 2024 |
| Swimseeker Ltd | Professional & scientific | 2023 |
| Swineshead Kebabs Ltd | Hospitality | 2025 |
| Swojskie Jadlo Ltd | Hospitality | 2025 |
| SYD Budge & Company Limited | Construction | 1971 |
| Sylvester Electrical Fire & Security Ltd | Administrative & support | 2020 |
| SYLVIA84 Limited | Health & social care | 2018 |
| Synergetic Holdings Limited | Real estate | 2019 |
| T & R Maintenance Limited | Transport & logistics | 2021 |
| T a Blackamore Limited | Administrative & support | 2013 |
| T Clarke & Sons (Construction) Limited | Extraterritorial | 2014 |
| T Clarke & Sons (Joinery) Limited | Extraterritorial | 2010 |
| T Clarke & Sons (Poultry) Limited | Extraterritorial | 2010 |
| T G Morgan Electrical Ltd | Construction | 2018 |
| T R & K a Ladds Limited | Financial services | 2017 |
| T W Labour Services Ltd | Transport & logistics | 2012 |
| T. & B. Containers Holdings Ltd | Manufacturing | 2016 |
| T. & B. Containers Limited | Manufacturing | 1977 |
| T. Bowles & SON Limited | Extraterritorial | 2016 |
| T. Houghton Limited | Construction | 1997 |
| T. L. Shellfish Holdings Limited | Administrative & support | 2010 |
| T.A.Priestley,Limited | Agriculture & fishing | 1943 |
| T.C.Cheer Company Limited | Agriculture & fishing | 1957 |
| T.H.Clements & SON Limited | Agriculture & fishing | 1966 |
| T.T. Motorsport Ltd. | Wholesale & retail | 1997 |
| TA Atlantic and Pacific Vii-A UK AIV, L.P. | | 2016 |
| TA Atlantic and Pacific Vii-B UK AIV, L.P. | | 2016 |
| TA Investors IV UK AIV L.P. | | 2013 |
| TA SDF III UK AIV L.P. | | 2013 |
| TA SDF IV UK AIV, L.P. | | 2016 |
| TA Xii-A UK AIV, L.P. | | 2016 |
| TA Xii-B UK AIV, L.P. | | 2016 |
| Taboo Grantham Limited | Hospitality | 2021 |
| Tadas Drive Limited | Transport & logistics | 2025 |
| Tadova Ltd | Transport & logistics | 2025 |
| Tagg Properties Ltd | Real estate | 2026 |
| Talk Russian Limited | Information & communication | 2011 |
| TAN & Beauty Express Ltd | Other services | 2026 |
| Tanglewood Care 2 Parent Limited | Health & social care | 2021 |
| Tanglewood Care Holdings Limited | Financial services | 2024 |
| Tanglewood Care Homes (Developments) Limited | Administrative & support | 2021 |