| SYK Professional Services Ltd | Financial services | 2015 |
| Syka FM Ltd | Administrative & support | 2026 |
| Sykes Partners Limited | Administrative & support | 2017 |
| Sykes Transfers DC Ltd | Transport & logistics | 2019 |
| Sylatone Limited | Information & communication | 2012 |
| Sylauto UK Ltd | Administrative & support | 2024 |
| Syldon & Co Ltd | Professional & scientific | 2013 |
| Sylval Social Care Ltd | Health & social care | 2022 |
| Sylvia & Co. Properties Management Ltd | Hospitality | 2023 |
| Sylvia Rankine Edu-Care Limited | Transport & logistics | 2024 |
| SYM Investment Limited | Real estate | 2025 |
| SYM Recruitment Ltd | Administrative & support | 2025 |
| Symbusis Limited | Information & communication | 2010 |
| Symmetric Ltd | Construction | 2013 |
| Symons, GAY & Leland LLP | | 2010 |
| Symoz Services Limited | Professional & scientific | 2012 |
| Synchronicity Music Limited | Information & communication | 2021 |
| Synet Group Ltd | Wholesale & retail | 2023 |
| Synthevia Ltd | Wholesale & retail | 2026 |
| Syntricglobal Ltd | Information & communication | 2026 |
| Syntrix Group Limited | Wholesale & retail | 2026 |
| Syntronic Limited | Wholesale & retail | 2025 |
| Syntrux Ltd | Information & communication | 2025 |
| SYR Barbers Limited | Other services | 2025 |
| Sysconnects Ltd | Information & communication | 2025 |
| Sysifos Ventures Limited | Health & social care | 2024 |
| System International Ltd | Wholesale & retail | 2024 |
| Systematic Care Solutions Ltd | Health & social care | 2020 |
| Systems Flow Engineering Ltd | Professional & scientific | 2011 |
| Systix Limited | Real estate | 2009 |
| SZ Logistics Limited | Transport & logistics | 2017 |
| SZ Services Ltd | Wholesale & retail | 2017 |
| Szergej Lozovoj Ltd | Construction | 2019 |
| SZR Tech Ltd | Wholesale & retail | 2022 |
| T & Co Solutions Ltd | Other services | 2025 |
| T & M Brickwork Ltd | Construction | 2023 |
| T & P Contractors Limited | Construction | 2017 |
| T & S Autos Garage Limited | Wholesale & retail | 2020 |
| T & S Star UK Ltd | Administrative & support | 2019 |
| T & T Labels Limited | Hospitality | 2022 |
| T & U Limited | Administrative & support | 2015 |
| T a Costello & Co. Ltd. | Professional & scientific | 1994 |
| T and K Plumbing Ltd | Construction | 2021 |
| T CHE Properties Limited | Real estate | 2025 |
| T Frankland Limited | Construction | 2015 |
| T K Drywall Limited | Construction | 2019 |
| T K Rasmussen and Sons Logistics Ltd | Transport & logistics | 2026 |
| T L Chauffeur Ltd | Transport & logistics | 2020 |
| T Link Ltd | Transport & logistics | 2022 |
| T Moore Consulting Ltd | Information & communication | 2019 |
| T Noble Ltd | Construction | 2014 |
| T R Durcan Group Limited | Construction | 2026 |
| T Resource Ltd | Education | 2015 |
| T S Auto Garage Ltd | Manufacturing | 2024 |
| T S UK Star Ltd | Manufacturing | 2024 |
| T Twelve Limited | Administrative & support | 2010 |
| T W Construction Services Ltd | Construction | 2025 |
| T& N Associates Ltd | Health & social care | 2026 |
| T&A Commerce Ltd | Wholesale & retail | 2025 |
| T&A Group Ltd | Construction | 2016 |
| T&A Properties & Management Limited | Real estate | 2026 |
| T&D Brickwork Ltd | Construction | 2023 |
| T&E Media Limited | Information & communication | 2022 |
| T&F: Your Paradise of Style Ltd | Wholesale & retail | 2025 |
| T&G Bedroom & Kitchen Ltd | Construction | 2024 |
| T&G Developers Ltd | Real estate | 2024 |
| T&G London Limited | Construction | 2015 |
| T&M Commerce Ltd | Manufacturing | 2024 |
| T&M Interiors Ltd | Construction | 2022 |
| T&P Builders Ltd | Construction | 2024 |
| T&S Commerce Ltd | Wholesale & retail | 2023 |
| T&S London Limited | Construction | 2023 |
| T&Z Finance Ltd | Financial services | 2023 |
| T-Ren Ltd | Wholesale & retail | 2025 |
| T-Star Security Services Ltd | Wholesale & retail | 2026 |
| T. Shipton Investments Limited | Administrative & support | 2001 |
| T.E.M.I Studios Ltd | Information & communication | 2018 |
| T1 Building and Mobility Limited | Construction | 2022 |
| T121 Group Ltd | Information & communication | 2018 |
| T2 Limited | Professional & scientific | 2005 |
| T29 Distributors Ltd | Extraterritorial | 2000 |
| T29 Logistic Partners Ltd | Transport & logistics | 1993 |
| TA & Associates Limited | Professional & scientific | 2012 |
| Taaz Couriers Ltd | Transport & logistics | 2025 |
| Taban Property Management Ltd | Households | 2024 |
| Tabernacle Construction Ltd | Construction | 2023 |
| Table IS SET CIC | Health & social care | 2026 |
| Tachichi Limited | Health & social care | 2012 |
| Tacho UK Ltd | Education | 2025 |
| Tackle Guru Limited | Wholesale & retail | 2008 |
| TACKLE2YOU Limited | Wholesale & retail | 2025 |
| Tactical Charms Ltd | Wholesale & retail | 2025 |
| TAD Metalworks Ltd. | Manufacturing | 2003 |
| Tadas Group Ltd | Construction | 2026 |
| Tadasmatas Ltd | Financial services | 2024 |
| Tadclub Ltd | Wholesale & retail | 2018 |
| TAF Heating and Plumbing Training Centre Ltd | Education | 2009 |
| TAG Business Computing Limited | Information & communication | 1983 |
| TAG Health Solutions Limited | Extraterritorial | 2014 |
| TAG London Limited | Real estate | 2022 |