| 50HZ Ltd | Wembley | 2024 |
| 512MOTORSPORT Ltd | Wolverhampton | 2026 |
| 513 Enterprise Limited | Sheffield | 2016 |
| 5149 Ltd | Nottingham | 2020 |
| 515 Construction Ltd | Cheadle | 2024 |
| 51KM Limited | Worksop | 2023 |
| 51T Ltd | Manchester | 2017 |
| 52 Degrees Brewing Limited | Walsall | 2014 |
| 52 Degrees North Brewing Limited | Manchester | 2025 |
| 521 Automation Engineering Services Limited | Gateshead | 1996 |
| 528 Group Limited | Walsall | 2023 |
| 52ABG Limited | Chesterfield | 2014 |
| 53 Layered Design Ltd | Northolt | 2025 |
| 5374 Ltd | Gillingham | 2026 |
| 55 Above Ltd | March | 2014 |
| 55 Carpentry Ltd | Lymm | 2022 |
| 55 Degrees North Collective Ltd | Livingston | 2026 |
| 55 Records Ltd | St. Albans | 2025 |
| 55 Trading Ltd | Romford | 2022 |
| 5526 Ltd. | Devon | 1992 |
| 556 Ltd | Cambridge | 2025 |
| 556TRADING Ltd | Newhaven | 2024 |
| 55NORTH Boat Building Limited | Cockermouth | 2021 |
| 55TH Parallel Coffee Ltd | Glasgow | 2023 |
| 5659 Holdings Limited | Poole | 2018 |
| 5659 Limited | Poole | 2018 |
| 57 Degrees Light Ltd | New Malden | 2017 |
| 5750 Components Limited | Darwen | 1994 |
| 5763 Associates Limited | Witney | 2006 |
| 58 and Co. Limited | London | 2016 |
| 58 Nørth Ltd | Wick | 2025 |
| 59 Degrees North Limited | Orkney | 2019 |
| 59 North Limited | Bradford | 2015 |
| 590 Forge Limited | London | 2025 |
| 5911 Kitchen Bedroom & Design Ltd | Hounslow | 2025 |
| 599 Limited | London | 2013 |
| 5A'S Printing Ltd | London | 2021 |
| 5AXISWORKS Ltd | London | 2014 |
| 5C Composites Ltd | Cambridge | 2024 |
| 5C Jewellers Limited | London | 2020 |
| 5DB Industries Ltd | London | 2017 |
| 5DT Solutions Limited | Wolverhampton | 2021 |
| 5EC ALU Ltd | Stevenage | 2018 |
| 5EC Group Ltd | London | 2025 |
| 5FOUR Motorcycles Limited | Droitwich | 2018 |
| 5GSC Ltd | Forest Hill | 2019 |
| 5H Holding Ltd | Birmingham | 2019 |
| 5IVE+2 Ltd | Cheltenham | 2014 |
| 5IVE9INE Ltd | Derby | 2018 |
| 5LIVEWELDINGS Ltd | Burnley | 2019 |
| 5MM Limited | London | 2013 |
| 5OOJIN Atelier Ltd | London | 2026 |
| 5STAR Double Glazing Ltd | Southall | 2021 |
| 5TH Avenue Clothing Limited | Leicester | 2014 |
| 5TH Axis Solutions Ltd | Cambridge | 2025 |
| 5TH Quarter Ltd | Halifax | 2025 |
| 5X Window and Fleet Cleaning Service Ltd | Sheffield | 2025 |
| 5XC Ltd | Cambridge | 2019 |
| 5YS Ventures Management Ltd | Manchester | 2021 |
| 6 Degrees Simulation Ltd | Dunmow | 2025 |
| 6 IS Kinda Blue Ltd. | Birkenhead | 2023 |
| 6 Towns Distribution Limited | Stoke-On-Trent | 2019 |
| 6 Trading Ltd | Bury St. Edmunds | 2011 |
| 60 Plus Textiles Limited | Nelson | 1983 |
| 6000BC Ltd | Sheffield | 2020 |
| 601 Industries Ltd | Swansea | 2021 |
| 603 Autosport Ltd | Edinburgh | 2020 |
| 618 Fungi Club Limited | London | 2024 |
| 618 Safesource Ltd | Reading | 2016 |
| 62 Degrees Ltd | Enfield | 2026 |
| 6396 Ltd | Holmfirth | 2025 |
| 64 Bakery Ltd | South Queensferry | 2025 |
| 64XII Ltd | London | 2025 |
| 6695 Locomotive Limited | Poole | 2019 |
| 67 Rangoon Kitchen Ltd | Abbots Langley | 2023 |
| 6701 Bonding Ltd | Sandbach | 2018 |
| 68 Plus Limited | London | 2024 |
| 686 Fabrication Services Ltd | London | 2026 |
| 6880 Betton Grange (Society) Limited | Swindon | 2003 |
| 69 London Ltd | London | 2023 |
| 6A Interiors Ltd | Fareham | 2025 |
| 6DB Studios Ltd | Wetherby | 2019 |
| 6DN Ltd. | Laurencekirk | 2002 |
| 6FT Llama Ltd | Norwich | 2020 |
| 6I-INNOVATIONS UK Limited | Barnet | 2015 |
| 6IXTY 5IVE Productions Ltd | Pewsey | 2024 |
| 6PD Holdings Ltd | Templecombe | 2025 |
| 6PD Ltd | Castle Cary | 2026 |
| 6SCIENCE Ltd | Melton Mowbray | 2019 |
| 7 Exhibitions Limited | Bourne End | 2003 |
| 7 Fire Protection Services Limited | Rochford | 2016 |
| 7 Hills Brewery Limited | Doncaster | 2020 |
| 7 Hope Studio Ltd | Bude | 2026 |
| 7 Peaks Powder Coating Limited | Sheffield | 2017 |
| 7 Seas Fabrications Limited | Ventnor | 2024 |
| 7 Star Bedz Ltd | Birmingham | 2020 |
| 7 Star Catering Equipment Ltd | Blackburn | 2023 |
| 7 Stars Shutters London Ltd | London | 2025 |
| 7 Steel (Properties) Limited | Cardiff | 2002 |
| 7 Steel (UK) Holdings Limited | Cardiff | 2002 |