| 4 Paws Mobile Spa Limited | Alton | 2012 |
| 4 Paws Surgeries Limited | Preston | 2023 |
| 4 Paws Vets Limited | Preston | 2022 |
| 4 Peaks Limited | Shropshire | 2001 |
| 4 Penni Ltd | Hull | 1995 |
| 4 Planning Delivery Limited | Sheffield | 2013 |
| 4 Point Physio Ltd | Tamworth | 2015 |
| 4 Point Plans Ltd | Somerton | 2007 |
| 4 Point Studios Limited | Rugby | 2014 |
| 4 Polworth Road Limited | London | 1998 |
| 4 Probate and Wills Ltd | Hull | 2018 |
| 4 Quarters Consultancy Ltd | Bristol | 2022 |
| 4 Quatre Limited | Andover | 1999 |
| 4 Qubes Ltd | London | 2018 |
| 4 R Reassurance Ltd | Knottingley | 2010 |
| 4 Real Creative Limited | Cardiff | 2014 |
| 4 Rufford Street Management Company Limited | Amersham | 2000 |
| 4 Russell Road Limited | London | 1989 |
| 4 S London Ltd | Bedford | 2015 |
| 4 Sales Growth Ltd | Northampton | 2016 |
| 4 Sales Matters Limited | Fareham | 2019 |
| 4 Seasons Design Limited | West Yorkshire | 2002 |
| 4 Seasons Environmental Services Ltd | Leicester | 2016 |
| 4 Seconds Limited | Tring | 2010 |
| 4 Shaw Limited | London | 2025 |
| 4 Sight Management Ltd | Windsor | 2002 |
| 4 Sight Shropshire Ltd | Telford | 2022 |
| 4 Sight. Eyecare Centres Holdings Limited | Road, Cannock | 1985 |
| 4 Sight. Franchising Limited | Road Cannock | 1987 |
| 4 Site Design Ltd. | Dunstable | 2001 |
| 4 Square Engineering Consultancy Limited | Inverness | 2003 |
| 4 ST Albans RD Management Company Ltd | Swansea | 2021 |
| 4 Stars Financial Ltd | Wisbech | 2022 |
| 4 Stockwell Terrace Limited | | 1996 |
| 4 Surveying Ltd | Chessington | 2024 |
| 4 Sustainable Beans Ltd | Barnet | 2023 |
| 4 Swiss Road Management Company Limited | Weston-Super-Mare | 1995 |
| 4 to 10 Ltd | Stockport | 2021 |
| 4 Walls Engineering & Construction Limited | Norwich | 2016 |
| 4 Way Energy Ltd | King'S Lynn | 2014 |
| 4 West Road Clapham Limited | London | 2011 |
| 4 YOU Accountants Limited | Solihull | 2012 |
| 4 Yscs Ltd | Ipswich | 2023 |
| 4&8 Limited | London | 2009 |
| 4-11 Live Ltd | Ashford | 2004 |
| 4-37 West Architects Ltd | Prestwick | 2023 |
| 4-4-2 Accounting Limited | Chorley | 2013 |
| 4-5 Grays Inn Square Limited | London | 2013 |
| 4-5-7 Comms Ltd | Waterlooville | 2023 |
| 4-8 Beauchamp Road Ltd | Malmesbury | 2008 |
| 4-C Consulting Limited | Exeter | 2021 |
| 4-D Projects Limited | Retford | 2025 |
| 4-EDGE Purpose Ltd | Godalming | 2025 |
| 4-FRONT Consulting Ltd | Bedfordshire | 2004 |
| 4-PLAY Promotions Limited | Woodford Green | 2010 |
| 4-RAIL Services Limited | London | 1996 |
| 4-THOUGHT Professional Services Limited | Yarmouth | 2001 |
| 4-TRO Ltd | Doncaster | 2019 |
| 4/5 Margarets Building Bath (Management) Limited | Castle Cary | 1989 |
| 40 Blomfield Road Limited | London | 1983 |
| 40 Degrees Limited | London | 1996 |
| 40 Lushington Road Limited | Eastbourne | 2003 |
| 40 Lyveden Road Freehold Limited | Saxlingham | 2002 |
| 40 Ockendon Road Limited | Dorking | 2000 |
| 40 Percent Ltd | Bristol | 2021 |
| 40 Prebend Gardens Ltd | London | 2007 |
| 40 Taxis Ltd. | Edinburgh | 2013 |
| 40 TPH Limited | Bessborough Road | 2013 |
| 40-42 Jackson Road Management Limited | | 2003 |
| 40-CONSTRUCTION Ltd | Trowbridge | 2019 |
| 400 Baring Road (Freehold) Limited | London | 2016 |
| 400 LUX Ltd | London | 2017 |
| 400 PPM Limited | London | 2021 |
| 4000M Consulting Services Limited | London | 2014 |
| 4000RPM TX Ltd | Woking | 2000 |
| 401 Digital LAB Limited | London | 2024 |
| 402K Consultancy Ltd | Birmingham | 2015 |
| 404 Associates Ltd | Tunbridge Wells | 2024 |
| 404 Engineering Limited | Swadlincote | 2019 |
| 404 Found Consulting Limited | Altrincham | 2025 |
| 404 Marketing Solutions Ltd | London | 2024 |
| 4040 Consulting Ltd | London | 2020 |
| 4040 Media Limited | Southport | 2009 |
| 4041 Ltd | King'S Lynn | 2016 |
| 4047 Consulting Limited | London | 2023 |
| 404MFX Limited | Louth | 2024 |
| 407 Consulting Limited | Leven | 2014 |
| 407 Finance Limited | Stourbridge | 2017 |
| 408 Consultancy Management Ltd | Wembley | 2024 |
| 40A and 40B Acacia Avenue Ruislip Freehold Ltd | Ruislip | 2020 |
| 40DOTS Ltd | London | 2015 |
| 40DP Consulting Ltd | Bristol | 2026 |
| 40G Pipelines & Facilities Limited | Gerrards Cross | 2015 |
| 40K Designs Ltd | London | 2025 |
| 40P Ltd | London | 2025 |
| 40ROCK Ltd | London | 2025 |
| 40SECONDS Ltd | Grangemouth | 2020 |
| 40TREE Management Limited | Edinburgh | 2020 |
| 41 & 41A Goldsborough Road Management Company Ltd | London | 2010 |
| 41 Cheriton Road Management Company Limited | Romney Marsh | 2005 |