| Sutton Group Limited | Professional & scientific | 2005 |
| Sutton Maintenance Limited | Administrative & support | 1989 |
| SV Vass Ltd | Construction | 2015 |
| Svetlana Lierre Limited | Arts & recreation | 2017 |
| SVM Support Services Ltd | Administrative & support | 2020 |
| SW Link Ltd | Manufacturing | 2008 |
| SW18 Engineering Limited | Professional & scientific | 2012 |
| Swai Thai Ltd | Hospitality | 2024 |
| Swain Stone Paving Ltd | Construction | 2025 |
| Swainstonepavingltd Ltd | Construction | 2025 |
| Swami Krupa Enterprise Ltd | Wholesale & retail | 2022 |
| Swan Housing Limited | Real estate | 2022 |
| Swann Payroll & Business Services Ltd | Administrative & support | 2017 |
| Swansea Fried Chicken Limited | Wholesale & retail | 2024 |
| Swarco Smart Charging Ltd | Manufacturing | 2022 |
| Swarco UK Holdings Limited | Professional & scientific | 2021 |
| Swarco UK Limited | Manufacturing | 1992 |
| Sway Fitness Limited | Health & social care | 2024 |
| Sweeney Engineering & Design Limited | Professional & scientific | 2007 |
| Sweet Sisters Trading Limited | Wholesale & retail | 2023 |
| Sweetbriar Advisory Limited | Professional & scientific | 2017 |
| Sweetness Catering UK Ltd | Hospitality | 2011 |
| Swift Yield Realty Ltd | Real estate | 2025 |
| Swifttyresmobile Ltd | Wholesale & retail | 2017 |
| Swiss Rock Assets Ltd | Construction | 2020 |
| Switch Technical Recruitment Limited | Administrative & support | 2015 |
| Switched Electrical Ltd | Construction | 2022 |
| SWM Associates (UK) LLP | | 2011 |
| SWM Metals Ltd | Water & waste | 2025 |
| Swooscale Ltd | Administrative & support | 2024 |
| Sworders Place Management Company Limited | Households | 2008 |
| SWR Garage Doors Limited | Professional & scientific | 2009 |
| SWR I.T. Limited | Professional & scientific | 2009 |
| SWR Limited | Manufacturing | 1988 |
| SWS Safety Ltd | Financial services | 2021 |
| Swws Property Limited | Real estate | 2016 |
| Syatt Entertainment Ltd | Information & communication | 2020 |
| Sycamore House (Merton) RTM Company Limited | Households | 2010 |
| Sycamore Park (Brookhouse) Management Company Limited | Households | 2018 |
| SYD Promotions Limited | Hospitality | 2005 |
| Sydroca Limited | Hospitality | 2025 |
| Sylwester Waste Management Ltd | Water & waste | 2016 |
| Symington Intelligence Ltd | Professional & scientific | 2020 |
| Symon Logistics Ltd | Transport & logistics | 2020 |
| Synapsis Media Limited | Information & communication | 2021 |
| Syncyr Limited | Information & communication | 2025 |
| Synergy Electric Ltd | Construction | 2018 |
| Synergy Project Consultants Limited | Administrative & support | 2017 |
| Synergy PV Renewables Ltd | Construction | 2023 |
| Synergydesk BPO Limited | Professional & scientific | 2024 |
| Synmia Technologies Limited | Information & communication | 2007 |
| Syntec Holdings Limited | Information & communication | 2003 |
| Syntec Investments Limited | Real estate | 2016 |
| Syntec Limited | Information & communication | 1998 |
| Syoncore Ltd | Mining & quarrying | 2021 |
| System Build Limited | Construction | 2017 |
| T & J Consulting Limited | Financial services | 2019 |
| T & L Trading UK Ltd | Wholesale & retail | 2022 |
| T & T Residential Holdings Ltd | Real estate | 2026 |
| T JAY Barber &Beauty Salon Ltd | Administrative & support | 2025 |
| T R B Mihai Limited | Administrative & support | 2015 |
| T W Data Limited | Information & communication | 2004 |
| T W Heating Services Ltd | Construction | 2016 |
| T&E Electrical Ltd | Construction | 2025 |
| T&F (Hemel Hempstead) Ltd | Professional & scientific | 2022 |
| T&I Healthcare Solution Ltd | Health & social care | 2023 |
| T&T Studios UK Limited | Information & communication | 2015 |
| T. Clark & Co Joinery Ltd | Manufacturing | 2010 |
| T.A.D. Communications Ltd | Wholesale & retail | 1997 |
| T.P. Roche & SON Limited | Construction | 1966 |
| T2 Propertytransformation (T2PT) Limited | Real estate | 2022 |
| Tacho Sensei Ltd | Professional & scientific | 2026 |
| TAD I-Am Ltd | Manufacturing | 2018 |
| Tafe Limited | Hospitality | 2025 |
| Take 23 Ltd | Information & communication | 2018 |
| Take Construction Ltd | Construction | 2019 |
| Takeid Ltd | Professional & scientific | 2019 |
| Talbot Construction Group Ltd | Construction | 2025 |
| Talbot Family Investments Ltd | Financial services | 2023 |
| Talent Trend Recruitment Ltd | Administrative & support | 2025 |
| Talk-Kit Ltd | Education | 2017 |
| Talking Drum Entertainment Limited | Information & communication | 2012 |
| Tame & Wild Ltd | Administrative & support | 2020 |
| Tandy Group Holdings Limited | Financial services | 2025 |
| Tania Accountant Ltd | Professional & scientific | 2024 |
| Tanjent Energy Ltd | Construction | 2019 |
| Tanlea Engineering Ltd | Professional & scientific | 1986 |
| Tanswell Technology Limited | Information & communication | 2008 |
| Tanzx Investments Limited | Real estate | 2025 |
| Taplow Consulting Limited | Administrative & support | 2005 |
| Taplow Executive Search Limited | Administrative & support | 1992 |
| Target Technology Petrel Limited | Extraterritorial | 1987 |
| Tarling Tipping Services Ltd | Water & waste | 2012 |
| Taruf Forum Ltd | Professional & scientific | 2026 |
| Tascroft Rise Management Company (Warminster) Limited | Real estate | 2017 |
| Tascroft Rise Phase 3 Management Company (Warminster) Limited | Real estate | 2021 |
| Tascroft Rise Phase 4 Management Company (Warminster) Limited | Real estate | 2022 |
| Tasker Property Ltd | Real estate | 2020 |
| Tasmania F.C Limited | Arts & recreation | 2020 |
| Tasty Fried Chicken (Luton) Limited | Hospitality | 2012 |