| 37 Norwich Road Limited | Downham Market | 2014 |
| 37 Victoria Road Limited | Esher | 2004 |
| 373 Caledonian Limited | London | 2013 |
| 376 Developments Limited | Oxford | 2016 |
| 376 Estates (Cheddar) Ltd | Oxford | 2025 |
| 376 Estates Limited | Oxford | 2016 |
| 37C Fitzjohns Limited | | 2002 |
| 37PD Consulting Ltd | Rugeley | 2025 |
| 37TH Crescent Group Limited | Walthamstow | 2020 |
| 38 Clarence Street Ltd | Cheltenham | 2021 |
| 38 Curzon Limited | London | 2015 |
| 38 High Street Littlehampton Ltd | Chichester | 2021 |
| 38 SS Renovations Ltd | London | 2026 |
| 38 Tile & Bathroom Company Limited | Leamington Spa | 2026 |
| 38 Twinoaks Ltd | Cobham | 2023 |
| 38.SPRINKLERS Limited | Maidstone | 2025 |
| 381 Global UK Limited | London | 2019 |
| 381 Partners Limited | Hackbridge | 2016 |
| 382N Ltd | London | 2020 |
| 388 Development Ltd | London | 2019 |
| 38NBS Ltd | Liverpool | 2020 |
| 39 Fitzjohns Avenue Limited | London | 2017 |
| 39 Fore Street Ltd. | Chard | 2018 |
| 39-51 Highgate Road Development Limited | London | 2014 |
| 397 Cockfosters Homes Ltd | London | 2018 |
| 398 Wilbraham Road Limited | Hyde | 2023 |
| 399 Edgware Road Management Company Limited | London | 2014 |
| 3A Building Contractors Ltd | Hampton | 2019 |
| 3A Building Services Ltd | Rainham | 2017 |
| 3A Electrical Services Ltd | Leeds | 2023 |
| 3A Projects Ltd | Harlow | 2019 |
| 3A Roofing Limited | Ipswich | 2003 |
| 3A Workforce Limited | Ellesmere Port | 2024 |
| 3A Works Ltd | Manchester | 2024 |
| 3A2M Group Ltd | London | 2026 |
| 3ACE Contractors (UK) Limited | London | 2014 |
| 3ACE MEP Contractors (UK) Limited | London | 2020 |
| 3AD Limited | Dagenham | 2024 |
| 3AG Builders Ltd | West Drayton | 2014 |
| 3AL Construction UK Ltd | London | 2024 |
| 3AM Contractors Limited | Wembley | 2020 |
| 3AM in Venice Ltd | Ashford | 2021 |
| 3AM Properties Limited | London | 2021 |
| 3AMOK Ltd | Slough | 2025 |
| 3AMP Electrical Ltd. | Gloucester | 2025 |
| 3ANDB Limited | Northampton | 2016 |
| 3ASTAR Electrical Services Limited | Leigh-On-Sea | 2015 |
| 3B ALL Rounder Ltd | Hounslow | 2025 |
| 3B Bathrooms Limited | London | 2023 |
| 3B Construction Ltd | Carlisle | 2003 |
| 3B Consultants Ltd | Worksop | 2011 |
| 3B Developments Ltd | Dereham | 2020 |
| 3B Homes Building Co Ltd | Cheltenham | 2019 |
| 3B Limited | Rochester | 2021 |
| 3B Maintenance Ltd | West Drayton | 2025 |
| 3BD Services Ltd | London | 2025 |
| 3BILT Ltd | London | 2025 |
| 3BL Electrical Limited | Redruth | 2017 |
| 3BM Holdings Limited | Peterborough | 2022 |
| 3BROS Steelfixing Ltd | London | 2021 |
| 3BROSKIES Ltd | Slough | 2025 |
| 3BS Joinery Ltd | Shetland | 2020 |
| 3BUILD Ltd | Lincoln | 2015 |
| 3BY Limited | Kingston Upon Thames | 2014 |
| 3C (London) Ltd | Beckenham | 2022 |
| 3C Build Limited | Bristol | 2017 |
| 3C Carpentry Ltd | Aldershot | 2024 |
| 3C Commercial Ltd | Somerset | 2015 |
| 3C Construction Limited | Truro | 2013 |
| 3C Electrical Ltd | Colchester | 2016 |
| 3C Electrical Services Ltd | Dagenham | 2020 |
| 3C Electrical Solutions Ltd | Aldershot | 2025 |
| 3C Evolution Limited | Southsea | 2020 |
| 3C Home Renovations Ltd | Altrincham | 2018 |
| 3C Projects Limited | Newport Pagnell | 2021 |
| 3C Property Developments Ltd | Somerset | 2011 |
| 3C Property Ltd | Oxted | 2022 |
| 3C Renovations Ltd | Maidstone | 2017 |
| 3C'S Property Maintenance Limited | Wolverhampton | 2019 |
| 3CANE Ltd | Magherafelt | 2025 |
| 3CIX Ltd | Milton Keynes | 2021 |
| 3COL Maintenance Services Ltd | London | 2024 |
| 3CORE Services Ltd | Cardiff | 2017 |
| 3CORESPARKY Limited | Motherwell | 2026 |
| 3COUNTIES Loft Boarding and Loft Ladders Limited | Malvern | 2019 |
| 3COUNTIESPROPERTIES Limited | Kettering | 2012 |
| 3CYCLE Ltd | Beckenham | 2020 |
| 3D - Hvac Services Limited | London | 2012 |
| 3D Art Factory Ltd | London | 2014 |
| 3D Bathrooms Limited | Scunthorpe | 2026 |
| 3D Brickwork Ltd | Birmingham | 2020 |
| 3D Brickwork West Midlands Ltd | Edgbaston | 2026 |
| 3D Builder Limited | Gravesend | 2021 |
| 3D Builders & Designers Ltd | Wigan | 2025 |
| 3D Building Bristol Ltd | Bristol | 2020 |
| 3D Building Design Ltd | Esher | 2021 |
| 3D Building Home Ltd | London | 2019 |
| 3D Building Ltd | London | 2023 |
| 3D Building Survey Ltd | London | 2018 |
| 3D Civil Engineering Limited | Southall | 2019 |