| 4TH Dimension Technology Limited | Northampton | 2018 |
| 4TH Dwarf Ltd | London | 2021 |
| 4TH Earth Limited | London | 2008 |
| 4TH Edge Ltd | Falkirk | 2025 |
| 4TH Element Consulting Limited | Colchester | 2014 |
| 4TH Generation (NW) Limited | Chorley | 2010 |
| 4TH Generation Services Ltd | Sherborne | 2018 |
| 4TH Line Consulting Limited | South Croydon | 1997 |
| 4TH Millennium Systems Limited | Norfolk | 1996 |
| 4TH Partner Limited | Kilmarnock | 2025 |
| 4TH Platform Limited | Horsham | 2012 |
| 4TH Revolution Analytics Limited | London | 2022 |
| 4TH Rock Limited | Ashbourne | 2007 |
| 4TH Street Limited | Cardiff | 2015 |
| 4TH Support Ltd | Camberley | 2014 |
| 4TH Utility Holdings Limited | London | 2017 |
| 4TH Utility Holdings Topco Limited | London | 2023 |
| 4TH Utility ISP Limited | London | 2024 |
| 4TH Utility ISP2 Limited | London | 2024 |
| 4TH Wall Productions Limited | Biggleswade | 2014 |
| 4TH World Media Ltd | Southall | 2025 |
| 4THELOVE4THEMONEY Limited | London | 2025 |
| 4THEUK Limited | Burgess Hill | 2005 |
| 4THOUGHTDIGITAL Ltd | Brent Knoll | 2023 |
| 4THQ Limited | | 2002 |
| 4TIFYIT Ltd | Launceston | 2025 |
| 4TL Software Limited | Birkenhead | 2003 |
| 4TONIC Data (NI) Limited | Belfast | 2024 |
| 4TSEC Limited | Redditch | 2024 |
| 4TUNED Solutions Ltd. | Bury St. Edmunds | 2018 |
| 4TW Limited | Corbridge | 2024 |
| 4TX Ltd | London | 2016 |
| 4TY Limited | Walthamstow | 2010 |
| 4U Solutions Limited | Leigh On Sea | 2006 |
| 4UCONSULT Ltd | London | 2025 |
| 4UMAH Ltd | Larbert | 2025 |
| 4URPHONE (2016) Ltd | Belfast | 2016 |
| 4VCO Limited | Lingfield | 1997 |
| 4VFX Limited | East Twickenham | 2017 |
| 4VIBES Productions UK Limited | London | 2022 |
| 4VISION Multimedia Limited | High Wycombe | 2022 |
| 4WALLDESIGN Limited | Liverpool | 2018 |
| 4WARD Communications Limited | London | 2004 |
| 4WARD Group Holdings Ltd | Redruth | 2020 |
| 4WARD IT Ltd | Belfast | 2022 |
| 4WARD IT Solutions Limited | Barking | 2015 |
| 4WARD Loop Ltd | Kings Lynn | 2014 |
| 4WARD Thinking Limited | Leigh-On-Sea | 2010 |
| 4WAY Pictures (Scotland) Limited | | 2004 |
| 4WAY Solutions Limited | Potters Bar | 2001 |
| 4WAY Support Services Ltd | Potters Bar | 2004 |
| 4WEB Solutions Limited | Wolverhampton | 2019 |
| 4WEBS Group Ltd | Dunstable | 2024 |
| 4WORD Thinking Limited | Silsoe | 2021 |
| 4WSERVICES Limited | Telford | 2016 |
| 4X Hostings Ltd | Wolverhampton | 2026 |
| 4X Solutions (UK) Ltd | Walthamstow | 2009 |
| 4X Writers Ltd | Wolverhampton | 2023 |
| 4XD IT Solutions Limited | Peterborough | 2025 |
| 4XPORTAL Ltd | Morden | 2021 |
| 4XXI Software Ltd | Richmond | 2017 |
| 4Y Consulting Ltd | Bromley | 2018 |
| 4YOU Agency Ltd | London | 2025 |
| 4ZA Music Limited | London | 2020 |
| 4ZERO Marketing Limited | Derby | 2023 |
| 5 Acts Films Ltd | Cardiff | 2024 |
| 5 Agile Ltd | Watford | 2014 |
| 5 AM Limited | London | 2008 |
| 5 Angels Conglomerate Limited | Wolverhampton | 2018 |
| 5 Brookside Consulting Limited | Dorking | 2016 |
| 5 by 5 Operations Solutions Ltd | London | 2010 |
| 5 Corporation Limited | London | 2013 |
| 5 Dinosaurs Ltd | Newcastle | 2021 |
| 5 Element Production Limited | Whitley Bay | 2013 |
| 5 Eyes Consulting Ltd | Bristol | 2021 |
| 5 Green Stars Limited | Manchester | 2019 |
| 5 I P Limited | Haslemere | 2011 |
| 5 K Broadcasting Ltd | Leeds | 2017 |
| 5 Lamps Media Ltd | Derby | 1981 |
| 5 Live Events Limited | Brighton | 2023 |
| 5 Magazine Limited | London | 2013 |
| 5 Media Ltd | Edinburgh | 2025 |
| 5 Miles Ahead Trailer Music Ltd | London | 2022 |
| 5 Miles Easy Ltd | London | 2024 |
| 5 Minute Fool Limited | Somerton | 2010 |
| 5 Natures Movies International Limited | Reading | 2021 |
| 5 O'Clock Apron Ltd | Bristol | 2023 |
| 5 P.M. Ltd. | Glasgow | 1999 |
| 5 Star Creative Ltd | Woking | 2023 |
| 5 Star IT Solutions Ltd | Newport | 2024 |
| 5 Star Kidz Ltd | Widnes | 2024 |
| 5 Star Laptops Ltd | Barking | 2024 |
| 5 Star Operations Ltd | Birmingham | 2023 |
| 5 Star Protect Limited | Hailsham | 2018 |
| 5 Star Suppliers Ltd | Glasgow | 2014 |
| 5 Stripes Solutions Ltd | Renfrew | 2026 |
| 5 Times Solutions Limited | Huddersfield | 2006 |
| 5 Virtue Productions Ltd | Bramhall | 2025 |
| 5 Waves Consulting Ltd | Ahoghill | 2024 |
| 5 Year Plan Limited | London | 2015 |