| Synergy P Limited | Health & social care | 2009 |
| Syntaxcore Limited | Information & communication | 2025 |
| Syntra Grid Ltd | Information & communication | 2026 |
| System 35 Ltd | Manufacturing | 2023 |
| System SIX Ltd | Professional & scientific | 2019 |
| System TEC Limited | Administrative & support | 2025 |
| System Vision Limited | Other services | 2010 |
| Systema Nervosum Limited | Health & social care | 2025 |
| Syzygy Hairdressing Limited | Other services | 2024 |
| Syzygy Interaction Ltd | Information & communication | 2016 |
| SZ330 Ltd | Wholesale & retail | 2026 |
| Szczech Commercial Ltd | Real estate | 2024 |
| SZN Cricket Ltd | Arts & recreation | 2025 |
| SZN Padel Ltd | Wholesale & retail | 2026 |
| Sôlt Restaurant Ltd | Hospitality | 2024 |
| T & C Little Bull Ltd | Hospitality | 2024 |
| T & C PUB Management Ltd | Hospitality | 2024 |
| T & C the Blake Ltd | Hospitality | 2022 |
| T & C the Horseshoe Ltd | Hospitality | 2023 |
| T & C the Sheaf Ltd | Hospitality | 2022 |
| T & G Hospitality Ltd | Hospitality | 2019 |
| T & K Motors HD Limited | Wholesale & retail | 2014 |
| T (Planning) Limited | Financial services | 2014 |
| T Beaumont Electrical Ltd | Construction | 2025 |
| T C Construction (Yorkshire) Ltd | Construction | 2021 |
| T F Lettings Ltd | Real estate | 2025 |
| T H Construction (UK) Ltd | Construction | 2010 |
| T H Energy Consultants Limited | Professional & scientific | 2019 |
| T M Connelly Ltd | Information & communication | 2021 |
| T Myring Consulting Limited | Professional & scientific | 2023 |
| T N Asset Management Ltd | Real estate | 2019 |
| T P S Courier Services Limited | Other services | 2023 |
| T Plant Ltd | Real estate | 2025 |
| T V Property Investments LLP | | 2021 |
| T Volt UK Limited | Manufacturing | 2021 |
| T Wood Construction Limited | Construction | 2014 |
| T&B Bookkeeping Services Limited | Professional & scientific | 2021 |
| T&R Anson Limited | Professional & scientific | 2024 |
| T&R Smiles Limited | Health & social care | 2025 |
| T'Wine Bar Ltd | Wholesale & retail | 2022 |
| T-H Masonry Limited | Construction | 2020 |
| T-Mo's Grill Limited | Hospitality | 2024 |
| T. Crapper & Co. Limited | Other services | 1998 |
| T. Pears Limited | Agriculture & fishing | 2003 |
| T.C.W. Services (Controls) Limited | Manufacturing | 1974 |
| T.J.Coy Ltd | Real estate | 2023 |
| T.M.S. Software Limited | Information & communication | 1985 |
| T.S. Plastering Contractors Ltd | Construction | 2021 |
| T.V.S Exports Ltd | Wholesale & retail | 2017 |
| T2100 Holdings Limited | Financial services | 2023 |
| T3 Event Catering Limited | Hospitality | 2023 |
| T4 - Trade Ltd. | Professional & scientific | 2006 |
| T4 TEE Travels Ltd | Transport & logistics | 2025 |
| T4P Ltd | Arts & recreation | 2014 |
| TA & P Properties Ltd | Households | 2025 |
| TA Asian Food Ltd | Hospitality | 2025 |
| TA Asset Management Ltd | Health & social care | 2023 |
| TAB Design Ltd. | Professional & scientific | 2012 |
| Table Bay Trading Limited | Wholesale & retail | 2010 |
| TABLETENNIS4U Ltd | Other services | 2026 |
| Tactic Consultancy Limited | Administrative & support | 2010 |
| TAG Capital Ltd | Wholesale & retail | 2023 |
| TAG Kitchen Developments Limited | Construction | 2018 |
| TAG Togs Ltd | Manufacturing | 2010 |
| Tagged Global Enterprises Ltd | Wholesale & retail | 2023 |
| Taham Group Ltd | Real estate | 2025 |
| Tahani Ibrahim Medical Ltd | Health & social care | 2025 |
| Tahsin HDS Ltd | Other services | 2022 |
| Tailab Delivery and Logistics Company Limited | Transport & logistics | 2024 |
| Tailorscribs Ltd | Information & communication | 2025 |
| Tajdaar Traders Limited | Wholesale & retail | 2024 |
| Talent Assess Limited | Administrative & support | 2022 |
| Talent Precision Group Ltd | Administrative & support | 2025 |
| Talent-Uk Limited | Administrative & support | 2019 |
| Talentologists Ltd | Administrative & support | 2013 |
| Talentsage UK Limited | Information & communication | 2023 |
| Talha's Pizza and Grill Bar Limited | Hospitality | 2019 |
| Tali UK Ltd | Information & communication | 2001 |
| Tall Ltd | Wholesale & retail | 2025 |
| Tallow Mews Block 2 Limited | Hospitality | 1995 |
| Tallow Mews Block 4 Limited | Households | 2005 |
| Tamalo Solutions Ltd | Administrative & support | 2023 |
| Tameside Chiropody & Podiatry Ltd | Health & social care | 2022 |
| Tamsin Stephenson Limited | Professional & scientific | 2017 |
| Tamstrad Limited | Administrative & support | 2025 |
| TAN Central Services Limited | Health & social care | 2018 |
| Tandem 1987 Limited | Financial services | 2016 |
| Tandem Homes Ltd | Real estate | 2024 |
| Tandem Specialist Automotive Re-Finishing Limited | Manufacturing | 2026 |
| Tandoor Chronicles Ltd | Hospitality | 2026 |
| Tangcai Ltd | Hospitality | 2024 |
| Tango Residential Ltd | Real estate | 2021 |
| Tani Logics Limited | Wholesale & retail | 2025 |
| Tann & Bradshaw Properties Limited | Real estate | 2026 |
| Tannis 2 Limited | Real estate | 2018 |
| Tannis Investments Limited | Other services | 2016 |
| Tanyard Ltd | Construction | 2019 |
| Tanzuk Consulting Ltd | Professional & scientific | 2010 |
| Taptech Solutions Ltd | Other services | 2025 |
| Taran Design Services Limited | Hospitality | 2020 |