| 383 Ltd | London | 2014 |
| 383 Project Limited | Birmingham | 2006 |
| 383 Solutions Limited | Rct | 2014 |
| 386 Edin Limited | Edinburgh | 2010 |
| 387 Veterinary Centre Limited | Great Wyrley | 2015 |
| 38BOX Ltd | Edgware | 2022 |
| 38ONE Design Limited | Tunbridge Wells | 2014 |
| 38THMOVE Ltd | London | 2025 |
| 38X Cyber Ltd | Beccles | 2011 |
| 39 Degrees Investments Ltd | Stockport | 2021 |
| 39 Degrees Ltd | Croydon | 2023 |
| 39 Degrees North Ltd | London | 2019 |
| 39 Essex Chambers (Services) Limited | London | 2010 |
| 39 Ferme Park Road Limited | | 1989 |
| 39 Granville Park Management Company Limited | London | 1992 |
| 39 Linkfield Street Management Company Limited | Redhill | 2014 |
| 39 Manor Drive Surbiton Limited | Surrey | 2004 |
| 39 Oakley Road Management Company Limited | London | 1986 |
| 39 Peaks Limited | Watford | 2010 |
| 39 Steps Consulting Ltd | Bradford | 2010 |
| 39 Steps Limited | Edinburgh | 2003 |
| 39 Sylvan Road Management Limited | London | 2012 |
| 39 Talbot Road N.6. Limited | | 1982 |
| 39 Westbourne Road Management Company Limited | Wirral | 1995 |
| 39/40 Park Street Bath Management Company Limited | Avon | 1990 |
| 390 Old London Road ORE Limited | Rickmansworth | 2008 |
| 391 Edin Limited | Broxburn | 2007 |
| 3940 Q SQ Corby (Freeholdco) Limited | Shirebrook | 2017 |
| 394FM Limited | Glasgow | 2020 |
| 3975 Holdings Ltd | Cradley Heath | 2019 |
| 39A Consulting Limited | Wotton Under Edge | 2018 |
| 39H Planning Consultancy Ltd | Croydon | 2021 |
| 39INVESTMENTS Limited | London | 2010 |
| 39MANSIONHOUSE Limited | Edinburgh | 2005 |
| 3A Business Excellence Ltd | Warwick | 2021 |
| 3A Capital Limited | Brighton | 2026 |
| 3A Compliance Associates Limited | London | 2026 |
| 3A Compliance Limited | London | 2025 |
| 3A Consultants Ltd | Northwood | 2015 |
| 3A Developments Ltd | Halifax | 2013 |
| 3A Engineering Limited | London | 2017 |
| 3A Evolve Limited | Bromley | 2019 |
| 3A Group Limited | London | 2016 |
| 3A Holding Ltd | London | 2017 |
| 3A Investment & Insurance Consultants Limited | Preston | 1985 |
| 3A Partnership Ltd | Inverness | 2012 |
| 3A Plus Business Partnering Ltd | London | 2015 |
| 3A Project Services Ltd | Romsey | 2024 |
| 3A Property Development Ltd | Mansfield | 2018 |
| 3A Technology Limited | Stockport | 2006 |
| 3A UK Holdings Ltd | Wolverton Mill | 2025 |
| 3A-D Heath Hurst Road Limited | | 1996 |
| 3A3P Limited | Letchworth Garden City, | 2013 |
| 3A4E Limited | Stamford | 2020 |
| 3ACTION Group Ltd | Leamington Spa | 2017 |
| 3ADAPT Limited | Bath | 2017 |
| 3ADESIGN Ltd | Stowmarket | 2016 |
| 3AF Ltd | London | 2018 |
| 3AI Ltd | London | 2018 |
| 3AM Entertainment Limited | London | 2023 |
| 3AM Ideas Ltd | Berkhamsted | 2009 |
| 3AM Thoughts Ltd | Berkhamsted | 2025 |
| 3AM-AN Ltd | Castleford | 2017 |
| 3AN Limited | Romford | 2016 |
| 3APM Ltd | Warminster | 2018 |
| 3AR Business Solutions Ltd | Welwyn Garden City | 2019 |
| 3ARENAS Limited | Chelmsford | 2026 |
| 3AV Investment Ltd | Welling | 2018 |
| 3AXIS Limited | London | 2020 |
| 3B Advisory Ltd | London | 2026 |
| 3B Assist and Learn Limited | Bolton | 2019 |
| 3B Consulting Limited | Bristol | 2024 |
| 3B Fire Consultancy Ltd | Dereham | 2019 |
| 3B Global Consulting Ltd | Belfast | 2025 |
| 3B Impact (Special Projects) Limited | Sheffield | 2021 |
| 3B Impact Holdings Limited | Sheffield | 2019 |
| 3B Incorporated Ltd | Romford | 2018 |
| 3B Management Limited | Bewdley | 2019 |
| 3B Risk Group Limited | Bury St. Edmunds | 2024 |
| 3B Support Services Limited | Consett | 2016 |
| 3B'S Digital Health Limited | Hatfield | 2021 |
| 3B1 MS Limited | Gravesend | 2025 |
| 3BDA Limited | Amersham | 2015 |
| 3BEARS Creative Ltd | Coventry | 2020 |
| 3BIM Engineering Ltd | Letchworth Garden City | 2025 |
| 3BIS Group Limited | London | 2026 |
| 3BIT Studio Limited | Nottingham | 2007 |
| 3BITES Ltd | Glasgow | 2018 |
| 3BL Ltd | London | 2026 |
| 3BL Media Limited | London | 2021 |
| 3BLUE Advisory Limited | Broadstairs | 2023 |
| 3BM Limited | Helsby | 2012 |
| 3BM Trustee Limited | Chelmsford | 2013 |
| 3BPB Limited | Barnet | 2020 |
| 3BRICKS Limited | Whalley Bridge | 2016 |
| 3BRIDGE Consultancy Ltd | Christchurch | 2008 |
| 3BW Holdings Ltd | London | 2023 |
| 3BZ Limited | Sunderland | 2026 |
| 3C Accounting Solutions Ltd. | Somerset | 2005 |
| 3C Bidding Ltd | London | 2021 |