| 3WM Communications Limited | London | 2019 |
| 3WM Consulting Ltd | Nottingham | 2019 |
| 3WM Projects Limited | London | 2024 |
| 3WMGLOBAL Limited | Greenhithe | 2016 |
| 3WR Consultants Limited | Twickenham | 2025 |
| 3X1 Group Limited | Falkirk | 2022 |
| 3X1 Limited | | 2000 |
| 3X1Y Ltd | London | 2020 |
| 3X5ACCOUNTANCY Ltd | Pudsey | 2022 |
| 3X6 Ltd | London | 2023 |
| 3X7X37 Limited | London | 2018 |
| 3XA Design Ltd | Shipley | 2020 |
| 3XC Ltd | London | 2023 |
| 3XCEPTION Limited | Macclesfield | 2013 |
| 3XE Ltd | Bradford | 2024 |
| 3XG UK Consulting Limited | Basingstoke | 2015 |
| 3XIMPACT Ltd | Oxford | 2023 |
| 3XM Financial Ltd | Isleworth | 2023 |
| 3XM Marketing Ltd | Birmingham | 2023 |
| 3XN London Limited | London | 2019 |
| 3XPC Ltd | Crawley | 2026 |
| 3XRE Ltd | Cardiff | 2024 |
| 3XT Limited | Wheathampstead | 2004 |
| 3XT Solutions Ltd | London | 2011 |
| 3Y Accountants Ltd | Birmingham | 2023 |
| 3YESSS Ltd | London | 2024 |
| 3YM Holdings Limited | Beckenham | 2024 |
| 3YM Limited | London | 2024 |
| 3Z Limited | Oxford | 2011 |
| 3ZEE Consulting Limited | Watford | 2023 |
| 3ZM Consultancy Ltd | Huddersfield | 2024 |
| 3ZM Limited | Hampton | 2006 |
| 4 & 1 Entertainment Limited | Southend-On-Sea | 2026 |
| 4 - 7 Creed Limited | Bury St. Edmunds | 2024 |
| 4 4 2 Media Group Limited | Darlington | 2017 |
| 4 4 Kids Ltd | London | 2015 |
| 4 Acland Road (Freehold) Limited | London | 2012 |
| 4 Acre Ecology Limited | Witney | 2012 |
| 4 Acre Environmental Limited | Shrewsbury | 2013 |
| 4 Alexandra Grove Limited | London | 2001 |
| 4 Architecture Ltd | Great Barrow | 2010 |
| 4 Assurance Services Ltd | Stockton-On-Tees | 2010 |
| 4 B Engineering Ltd | Liverpool | 2024 |
| 4 Beaumont Crescent Limited | | 2003 |
| 4 Beresford Road Management Company Limited | Birkenhead | 1994 |
| 4 BG Group Ltd | Sudbury | 2010 |
| 4 Brick Court Chambers Management Limited | Brookmans Park | 2003 |
| 4 Brothers Bench Locksmiths Ltd | London | 2023 |
| 4 Cast Systems Limited | Watford | 2014 |
| 4 Connected Limited | Stonehouse | 2016 |
| 4 Connections UK Ltd | Westbury | 2004 |
| 4 Consultancy Services Ltd | London | 2018 |
| 4 Corners Consultancy Ltd | London | 2026 |
| 4 Corners Holdings Ltd | Ilford | 2022 |
| 4 Corners Images Limited | London | 2004 |
| 4 Cough Limited | London | 2001 |
| 4 Day Week Collective Ltd | Thames Ditton | 2024 |
| 4 Dean Design Limited | Taunton | 2018 |
| 4 Design Concepts Limited | Westbury-On-Trym | 2017 |
| 4 Design Studio Ltd | London | 2024 |
| 4 Dimensional Leadership Limited | Baughurst | 2019 |
| 4 Dog Cottages Limited | East Grinstead | 2020 |
| 4 Dots Training & Advisory Limited | Devizes | 2019 |
| 4 Downside Road Clifton Limited | Bristol | 1999 |
| 4 E'S Facilitation Limited | Watford | 2021 |
| 4 Elmfield Court (Lindford) Limited | Bordon | 2007 |
| 4 Energy Solutions Limited | Armagh | 2019 |
| 4 Eyes Compliance Solutions Ltd | London | 2024 |
| 4 Eyes Limited | Barnet | 2003 |
| 4 Fans Productions Ltd | Sheffield | 2020 |
| 4 Gazi Limited | London | 2021 |
| 4 George Ltd | Hinton St. George | 2011 |
| 4 Global Safe Air Limited | Newcastle Upon Tyne | 2018 |
| 4 Global Solutions Ltd | Stockport | 2014 |
| 4 Green Architecture Limited | Hollinwood | 2013 |
| 4 Green Houses Limited | Wimborne | 2007 |
| 4 H Media Ltd | Bury | 2023 |
| 4 High Street Twerton Bath (Management) Limited | Bath | 1985 |
| 4 HR Solutions Limited | Keele | 2024 |
| 4 Hungershall Park Management Company Limited | Tunbridge Wells | 1991 |
| 4 Imprint USA Limited | London | 1994 |
| 4 J'S Consulting Ltd | Weston-Super-Mare | 2021 |
| 4 Jays Consulting and Developments Ltd | Warrington | 2024 |
| 4 Josephs Ltd | Beckenham | 2022 |
| 4 K Enterprise Limited | Cheadle Hulme | 2013 |
| 4 Kenilworth Road (Management Company) Limited | Bristol | 1973 |
| 4 Killowen Road Limited | London | 2008 |
| 4 Kings Consultancy Limited | Reading | 2010 |
| 4 Lochs Care Solutions Ltd | London | 2026 |
| 4 LUX Ltd | Kidderminster | 2010 |
| 4 Mation Architecture Limited | Stockport | 2003 |
| 4 Mexfield Road Limited | London | 2003 |
| 4 Momentum Limited | Worthing | 2005 |
| 4 Nines VB Ltd | Birmingham | 2025 |
| 4 Northumberland Terrace Limited | Chislehurst | 1997 |
| 4 Oceans Capital Ltd | Aylesbury | 2012 |
| 4 Offshore Ltd | Dundee | 2014 |
| 4 Parks Limited | London | 2025 |
| 4 Paws Animal Rehabilitation and Hydrotherapy Limited | Salisbury | 2015 |
| 4 Paws Holdings Ltd | Esher | 2026 |