| Studio Mintelier Limited | Professional & scientific | 2023 |
| Studio Skosh Ltd | Manufacturing | 2024 |
| Study Mind Holdings Ltd | Education | 2026 |
| Study Mind Limited | Education | 2017 |
| Stuflats Ltd | Real estate | 2017 |
| Sturd Holdings Limited | Professional & scientific | 2022 |
| Styles and Whitlock Limited | Real estate | 1996 |
| Success World Limited | Education | 2020 |
| Sulkan Limited | Professional & scientific | 2023 |
| Summerhouse Properties Ltd | Real estate | 2021 |
| Sun Air Sustainability Ltd | Administrative & support | 2011 |
| Sun Cove LLP | | 2023 |
| Sunbliss Developments Ltd | Wholesale & retail | 2016 |
| Sunbliss Vehicles Ltd | Wholesale & retail | 2020 |
| Sunford Enterprises Ltd | Wholesale & retail | 2025 |
| Sunlight Developments Ltd | Wholesale & retail | 2018 |
| Sunrise Consultants Limited | Information & communication | 2002 |
| Supplimatics Ltd. | Information & communication | 2001 |
| Surestock Solutions Limited | Professional & scientific | 2004 |
| Surman Capital Partners Ltd | Administrative & support | 2024 |
| Suru Ltd | Professional & scientific | 2020 |
| Surya Logistics Services Limited | Wholesale & retail | 2024 |
| Susan Daughtrey Education LLP | | 2012 |
| Susan Ellis Consultancy Limited | Professional & scientific | 2007 |
| Sustainable Packaging Products Ltd | Manufacturing | 2019 |
| Sustainable-Matters Limited | Professional & scientific | 2020 |
| Sutherland Management Services Limited | Professional & scientific | 2014 |
| Svac Link Limited | Real estate | 2025 |
| Sweep IT Limited | Information & communication | 2019 |
| Swim Street Ltd | Construction | 2018 |
| Swoop Energy & Recycling Limited | Water & waste | 2025 |
| SXK Group Ltd | Real estate | 2022 |
| Syer Fitness Ltd | Arts & recreation | 2024 |
| Sylhet Property Company Limited | Real estate | 2021 |
| Synapse Medical Consultancy Limited | Other services | 2016 |
| Synaptal Technologies Limited | Information & communication | 2015 |
| Syncomia Limited | Professional & scientific | 2024 |
| Synergasia Limited | Real estate | 2021 |
| Synergie Logistics Ltd | Administrative & support | 1997 |
| Synergy Building Services Solutions Limited | Construction | 1997 |
| Synergy Services Holdings Limited | Administrative & support | 2020 |
| Synergy Services Solutions Group Limited | Administrative & support | 2024 |
| Synqor UK, Limited | Administrative & support | 1999 |
| T P Design Holdings Limited | Professional & scientific | 1998 |
| T P M Childwise Ltd | Professional & scientific | 1989 |
| T-Minus Limited | Professional & scientific | 2021 |
| T-Roc UK Services Ltd | Wholesale & retail | 2025 |
| TA Associates (UK), LLP | | 2012 |
| TA Associates UK Advisors Limited | Financial services | 2003 |
| TA Installations Ltd | Administrative & support | 2026 |
| TAC (Medical Services) UK Limited | Health & social care | 2015 |
| TAC Healthcare Limited | Financial services | 2022 |
| Talent-Id Recruitment Limited | Administrative & support | 2026 |
| Talex Emea Ltd | Administrative & support | 2019 |
| Talking Places Ltd | Information & communication | 2018 |
| Tamu Minerals Ltd | Mining & quarrying | 2024 |
| Tandoori Clay Oven Co. Limited(The) | Manufacturing | 1983 |
| Tanian Ltd | Professional & scientific | 2026 |
| TAO Technology Ltd. | Information & communication | 2012 |
| Taro Projects Ltd | Construction | 2023 |
| Tarquin Healthcare Ltd | Professional & scientific | 2017 |
| Tasmar Limited | Professional & scientific | 2004 |
| Tastie Kitchen Ltd | Hospitality | 2025 |
| Tatianaceo Limited | Professional & scientific | 2019 |
| Tatla Interiors Ltd | Professional & scientific | 2016 |
| Tax Efficiency Limited | Other services | 1994 |
| Taylor ASH Consulting Ltd | Professional & scientific | 2019 |
| Taylor Kerr (Couplings) Limited | Wholesale & retail | 1978 |
| Taylor Kerr (Energy Products) Limited | Financial services | 1976 |
| Taylor Kerr (Engineering) Limited | Manufacturing | 1998 |
| Taylor Kerr Limited | Financial services | 2017 |
| TCT Advisory Ltd | Professional & scientific | 2023 |
| Team Reed Developments Limited | Real estate | 2010 |
| Team Training International Limited | Professional & scientific | 2010 |
| Technowood Cladding UK Limited | Professional & scientific | 2019 |
| Teekay Couplings Limited | Wholesale & retail | 1998 |
| Teign Investments Ltd | Financial services | 2023 |
| Teletrax TV Data UK Limited | Information & communication | 2001 |
| Tellerland Property Management Limited | Households | 2000 |
| Tempus Capital Holdings Limited | Professional & scientific | 2017 |
| Tempus I Limited | Real estate | 2017 |
| Tempus III Limited | Professional & scientific | 2017 |
| Tempus IV Limited | Professional & scientific | 2017 |
| Tempus Management Services Limited | Professional & scientific | 2017 |
| Tempus VII Limited | Real estate | 2019 |
| Tensis Limited | Information & communication | 2024 |
| Tent PEG Events (Stretch Tents) LLP | | 2015 |
| Tent PEG Events Ltd | Administrative & support | 2015 |
| TEP Services Limited | Information & communication | 2023 |
| Termite Media Limited | Financial services | 2021 |
| Teserra Software Limited | Information & communication | 2026 |
| Tessel Ltd | Information & communication | 2022 |
| Tetcott Limited | Real estate | 2015 |
| TGK Media Ltd | Information & communication | 2015 |
| Tharman FIC 2017 | Financial services | 2017 |
| THE Abstract BEE Ltd | Wholesale & retail | 2018 |
| THE Aloha Girls Ltd | Health & social care | 2024 |
| THE Anello Partnership LLP | | 2020 |
| THE Annuity Business Limited | Information & communication | 2013 |
| THE Beaconsfield Clinic Limited | Health & social care | 2019 |