| 4SYTE Receivables Finance Ltd | Chelmsford | 2020 |
| 4SYTE Scotland Ltd | Glasgow | 2025 |
| 4SYTE Secured Finance Ltd | Chelmsford | 2018 |
| 4SYTE Secured Lending Ltd | Chelmsford | 2024 |
| 4SYTE TM Ltd | Chelmsford | 2025 |
| 4SYTE Trade Ltd | Chelmsford | 2018 |
| 4T Markets Limited | London | 2014 |
| 4T&I Limited | London | 2017 |
| 4TALL Trees Limited | London | 2022 |
| 4TEL Group Limited | Penryn | 2023 |
| 4TH and Bainbridge Limited | London | 2017 |
| 4TH Dimension Innovation Limited | Egham | 2003 |
| 4TH Floor Financial Ltd | Derby | 2021 |
| 4THETRADE Ltd | London | 2025 |
| 4TIFY Group Ltd | Ellesmere Port | 2024 |
| 4TIS Group Holdings Limited | Walsall | 2026 |
| 4U Accountants Ltd | Maldon | 2016 |
| 4U Group of Companies Limited | Halifax | 2024 |
| 4U Healthcare Group Ltd | Skelmersdale | 2020 |
| 4U Tech Holdings Limited | Milton Keynes | 2024 |
| 4U2B Limited | Worcester | 2003 |
| 4US Holding Ltd | Poole | 2024 |
| 4WALL Holdings UK Limited | Chelmsford | 2019 |
| 4WARD Holdings Limited | Bury | 2018 |
| 4WARD Thinking Group Ltd | Nottingham | 2015 |
| 4WAY Group Holdings Ltd | Potters Bar | 2020 |
| 4WAYS Financial Planning Ltd | Edinburgh | 2022 |
| 4WAYS Financial Services Limited | Heckmondwike | 2020 |
| 4WEALTH Limited | Leigh-On-Sea | 2003 |
| 4WS Ltd | Exeter | 2020 |
| 4X Trading NI Limited | Holywood | 2024 |
| 4X4 Products Limited | Louth | 2020 |
| 4XD Ltd | Nottingham | 2024 |
| 4XMD Ltd | Spalding | 2025 |
| 4XTRADZ Capital Limited | London | 2026 |
| 4Y Group Ltd | Manchester | 2019 |
| 4YEYES Holdings Ltd | London | 2024 |
| 4YOU2COLLECT Ltd | Doncaster | 2023 |
| 4ZL Holdings Ltd | Portsmouth | 2024 |
| 5 Bears Ltd | Glasgow | 2025 |
| 5 Consulting (Investments) Ltd | Lydney | 2018 |
| 5 Core Group Holding Limited | London | 2024 |
| 5 Cranbrook Road Ltd | Bristol | 2012 |
| 5 Degrees Holdings Limited | St Austell | 2024 |
| 5 Keys Holdings Ltd | Birmingham | 2026 |
| 5 MH Limited | Manchester | 2025 |
| 5 NET Credit Opportunities Ltd | Watford | 2023 |
| 5 Penta Court Limited | Borehamwood | 2018 |
| 5 ST Patrick’S Road South Ltd | Ware | 2024 |
| 5 Star Financial Solutions Ltd | Stockport | 2019 |
| 5 Star Future Ltd | Manchester | 2016 |
| 5 Star Mortgage Solutions Limited | Stockport | 2014 |
| 5 Villages Group Ltd | Southampton | 2023 |
| 5 Welbeck Limited | London | 2015 |
| 5-7 Cheapside Manchester Limited | London | 2017 |
| 5-GROUP (Scotland) Limited | Glasgow | 2024 |
| 50 Plus Later Life Planning Limited | Blackwood | 2015 |
| 50 State & Co Ltd | Leicester | 2026 |
| 500 Entrepreneur Nominee Limited | St. Albans | 2023 |
| 500 Holdings Limited | Thatcham | 2025 |
| 500MORE Capital Limited | Bromley | 2024 |
| 5015 Finance Limited | Cookstown | 2016 |
| 5015 Limited | Didcot | 2025 |
| 502 Ltd | Leicester | 2021 |
| 505A Consulting Limited | Salford | 2013 |
| 50A Holdings Ltd | London | 2016 |
| 50CC Games Limited | Sudbury | 2013 |
| 50FIVEPLUS Limited | Stanford-Le-Hope | 2011 |
| 50WEST Limited | London | 2026 |
| 51 Arnfield Ltd | Manchester | 2024 |
| 51 Thailand Property Co., Ltd | Stafford | 2017 |
| 518AM (UK) Limited | London | 2024 |
| 51:58 Holdings Ltd | Hounslow | 2026 |
| 51DHU Holdings Ltd | Birmingham | 2026 |
| 51FIFTY Ltd | Blackburn | 2025 |
| 51FOLDS.AI Research Limited | Kent | 2025 |
| 52 Communications Limited | Stourbridge | 2022 |
| 52 Dogs Holding Ltd. | London | 2023 |
| 52 Finance Limited | Mold | 2010 |
| 52 Helix Road Management Company Limited | London | 2017 |
| 52 Portland Place Partners Ltd | Bognor Regis | 2024 |
| 525 Lavender GP Investments Ltd. | Cheltenham | 2019 |
| 528 Investments Limited | Walsall | 2024 |
| 5354 Edinburgh Limited | Edinburgh | 2016 |
| 5360 Holdings Limited | Twickenham | 2018 |
| 54 Degrees North Ltd | Leeds | 2026 |
| 54 Impactec Holdings Ltd | London | 2025 |
| 54 Lower High Street Shirehampton Ltd | London | 2024 |
| 54KFRD Limited | London | 2026 |
| 55 - 57 Pont Street (Resident) Limited | London | 2016 |
| 55 Amps | London | 2022 |
| 55 Block Holdings Limited | Wallsend | 2025 |
| 55 Fearon Road Ltd | Waterlooville | 2022 |
| 55 Gresham Limited | London | 2018 |
| 55 Gresham Ventures Limited | London | 2018 |
| 55 Group Holdings Limited | Tynemouth | 2025 |
| 55 ST Andrews Ltd | Glasgow | 2022 |
| 55 the Martlett Limited | Shoreham-By-Sea | 2012 |
| 55CAP Limited | London | 2017 |
| 56 Beversbrook Road Management Company Limited | Tufnell Park | 2007 |