| Sybo Investments Limited | Administrative & support | 2013 |
| Sycamore GAS Limited | Construction | 2025 |
| Sycamore Hill Property Limited | Real estate | 2026 |
| Sycamore Reitco Limited | Financial services | 2022 |
| Symbol Construction Limited | Construction | 2004 |
| Symes Design Engineering Limited | Professional & scientific | 2017 |
| Symphony Consulting Service Ltd | Health & social care | 2013 |
| Symphony Court (Gateshead) RTM Company Limited | Real estate | 2014 |
| Synapse Talent Ltd | Information & communication | 2025 |
| Synergy Green Energy Limited | Construction | 2017 |
| Synergy Sign Solutions Ltd. | Professional & scientific | 2021 |
| Syngas Bentinck Limited | Other services | 2020 |
| Syngas Group Limited | Other services | 2023 |
| Syngas Renewable Holding Limited | Other services | 2023 |
| SYO Store Ltd | Wholesale & retail | 2019 |
| Syrian Renaissance Centre for Studies and Research Limited | Professional & scientific | 2026 |
| SYS Healthcare Ltd | Wholesale & retail | 2025 |
| SZO Ltd | Real estate | 2023 |
| T & M Hill Limited | Administrative & support | 1996 |
| T & N Acquisitions Limited | Financial services | 2018 |
| T Irfan Locums Ltd | Health & social care | 2022 |
| T M Building & Maintenance Ltd | Construction | 2015 |
| T R Glazing & Cladding Limited | Construction | 2020 |
| T&N Star Ltd | Wholesale & retail | 2018 |
| T&S Foods Limited | Hospitality | 2025 |
| T-Tek (North East) Limited | Other services | 2017 |
| T. Lycett Properties Limited | Real estate | 1978 |
| T.A.S. PUB Company Limited | Hospitality | 2018 |
| T.H.T.F Ltd | Manufacturing | 2016 |
| T7 Electrical Limited | Construction | 2024 |
| TA HA Clothing Ltd | Wholesale & retail | 2024 |
| Table Turners Ltd | Information & communication | 2025 |
| TAG Paints UK Ltd | Wholesale & retail | 2024 |
| Taileroo Ltd | Wholesale & retail | 2022 |
| Taileroo PM Ltd | Administrative & support | 2024 |
| Tait Farrier Graham LLP | | 2020 |
| Taj-E-Haq Ltd | Extraterritorial | 2006 |
| Takeoff Digital Ltd | Information & communication | 2019 |
| Takmal Biosystems Ltd | Professional & scientific | 2026 |
| Talarius Limited | Financial services | 2005 |
| Talbot Jones Ltd | Financial services | 2015 |
| Talbot News Limited | Wholesale & retail | 2015 |
| Talent Partnerships (UK) Limited | Professional & scientific | 2000 |
| Talking Works Ltd | Health & social care | 2014 |
| Talten UK Ltd | Real estate | 2015 |
| Tamil Express Limited | Wholesale & retail | 2023 |
| Tamor Ltd | Real estate | 2011 |
| Tams Tyres Limited | Wholesale & retail | 2007 |
| TAN UK Direct Online Store Limited | Other services | 2023 |
| Tanella Beauty Ltd | Other services | 2020 |
| Tanfield Body Repair Limited | Wholesale & retail | 2007 |
| Tanfield Railway Company Limited | Arts & recreation | 1975 |
| Tangent Property Limited | Real estate | 2016 |
| Tanman Healthcare Limited | Health & social care | 2014 |
| Tantum Construction Ltd | Construction | 2019 |
| Tanz Investments Limited | Financial services | 2017 |
| Taos Property Limited | Real estate | 2024 |
| Tardigrade Communications Ltd | Information & communication | 2021 |
| Tardis Resources Ltd | Professional & scientific | 2011 |
| Target Residential Ltd | Real estate | 2019 |
| Taste Malaga Ltd | Wholesale & retail | 2016 |
| Tatton Commercial Limited | Real estate | 2023 |
| Tavistock Holdings (NE) Ltd | Financial services | 2022 |
| Tax Back Today Ltd | Professional & scientific | 2016 |
| Taxa Training and Consultancy Ltd | Education | 2015 |
| Taxi Accountant Ltd | Professional & scientific | 2025 |
| Taxi Trader Ltd | Administrative & support | 2011 |
| Taylor M&E Compliance Ltd | Professional & scientific | 2025 |
| Taylor Woodworking Castleford Ltd | Manufacturing | 2009 |
| TB Holliday Holdings Ltd | Professional & scientific | 2022 |
| TB Support Ltd | Administrative & support | 2026 |
| TBL Hire Ltd | Administrative & support | 2025 |
| Tcuk Homes Limited | Real estate | 2013 |
| Tdgs Properties Ltd | Real estate | 2020 |
| TDX (Europe) Limited | Professional & scientific | 2013 |
| Team Cycles (North East) Limited | Wholesale & retail | 2013 |
| Team Digital Ltd. | Manufacturing | 2004 |
| Team Lawson-Wood Ltd | Health & social care | 2024 |
| Team Replay Ltd | Other services | 2015 |
| Team RH Fitness Ltd | Other services | 2017 |
| Team RH TLC Ltd | Wholesale & retail | 2020 |
| Team Valley Bathroom Solutions Ltd | Construction | 2021 |
| Team Valley Car Valeting & Detailing Ltd | Wholesale & retail | 2022 |
| Team Valley Carpets Limited | Construction | 2003 |
| Team Valley Commercials Ltd | Wholesale & retail | 2021 |
| Team Valley Group Ltd | Extraterritorial | 2015 |
| Team Valley IT Ltd | Information & communication | 2013 |
| Team Valley Management Limited | Real estate | 1987 |
| Team Valley Marketing Ltd | Professional & scientific | 2020 |
| Team Valley MOT Ltd | Wholesale & retail | 2019 |
| Team Valley Pizza Ltd | Hospitality | 2017 |
| Team Valley Printers Ltd | Manufacturing | 2009 |
| Team Valley Properties Limited | Real estate | 2017 |
| Team Valley Tuning Ltd | Wholesale & retail | 2013 |
| Team Valley Tyres Ltd | Wholesale & retail | 2020 |
| Team Valley Web Limited | Information & communication | 2013 |
| Team Valley Windows and Conservatories Limited | Manufacturing | 2004 |
| Teams & Bensham Community Care | Health & social care | 2007 |
| Teams Innovage Limited | Wholesale & retail | 2022 |
| Teams Management Ltd | Real estate | 2009 |