| 500 Mills Limited | Other services | 2013 |
| 500 Restaurant Ltd | Hospitality | 2008 |
| 5000 Group Ltd | Wholesale & retail | 2025 |
| 5000 Theatre Ltd | Arts & recreation | 2025 |
| 5001 Capital Limited | Professional & scientific | 2024 |
| 500NITS Ltd | Information & communication | 2006 |
| 501 Kings Road RTM Company Limited | Households | 2021 |
| 501 Ltd. | Information & communication | 2021 |
| 502 Kingsland Road RTM Company Limited | Households | 2023 |
| 503 Avenir House Limited | Real estate | 2023 |
| 503 KR Limited | Real estate | 2021 |
| 505 Lincoln Ltd | Transport & logistics | 2025 |
| 505 Shapered Market Limited | Real estate | 2026 |
| 507 Fulham Road Limited | Households | 2011 |
| 507CLIMATE LLP | | 2023 |
| 507CLIMATE Solutions Ltd | Professional & scientific | 2026 |
| 508 Streatham High Road Management Limited | Households | 2002 |
| 509 BRE Ltd | Construction | 2024 |
| 50A Developments York Ltd | Real estate | 2016 |
| 50A Firs Lane Limited | Real estate | 2018 |
| 50A Holdings Ltd | Financial services | 2016 |
| 50A Whitton Limited | Real estate | 2026 |
| 50B Firs Lane Limited | Real estate | 2019 |
| 50B Productions Ltd | Information & communication | 2018 |
| 50BSCW Service Charge Limited | Real estate | 2017 |
| 50C Firs Lane Limited | Real estate | 2020 |
| 50FIVE Charging Solutions UK Ltd | Construction | 2025 |
| 50FOOTBALL Ltd | Arts & recreation | 2025 |
| 50FT Ltd | Professional & scientific | 2024 |
| 50K Lofts and Extensions Ltd | Extraterritorial | 2024 |
| 50PLUS Online Cafe Limited | Information & communication | 2018 |
| 50PLUS1 Ltd | Information & communication | 2025 |
| 50SHADESOFSUMMER Ltd | Wholesale & retail | 2022 |
| 50SHADEZ Ltd | Wholesale & retail | 2019 |
| 50TO500 Ltd | Administrative & support | 2018 |
| 50WEST Limited | Financial services | 2026 |
| 51 AG Management Limited | Households | 2016 |
| 51 and 53 Balfe Street Limited | Households | 2006 |
| 51 and 53 LA Gare Company Limited | Households | 2003 |
| 51 Avenue Ltd | Real estate | 2023 |
| 51 Aylesford Street Limited | Households | 2010 |
| 51 Barry Road Management Company Limited | Real estate | 1995 |
| 51 Beltran Road Management Limited | Households | 2024 |
| 51 Bergen Ltd | Real estate | 2018 |
| 51 Bounds Green Road Management Limited | Real estate | 2010 |
| 51 Brondesbury Villas Freehold Management Company Limited | Other services | 2011 |
| 51 Buckland Crescent (Freehold) Limited | Real estate | 2006 |
| 51 Burntwood Lane Management Limited | Households | 2002 |
| 51 Cadogan Gardens RTM Company Limited | Real estate | 2014 |
| 51 Carleton Road Limited | Real estate | 2011 |
| 51 Carnarvon Road Freehold Ltd | Extraterritorial | 1998 |
| 51 Cavendish Road Limited | Households | 2003 |
| 51 Central Hill (Freehold) Limited | Real estate | 2015 |
| 51 CH Ltd | Real estate | 2025 |
| 51 Cleveland Street Management Company Ltd | Households | 2007 |
| 51 Coningham Road Limited | Real estate | 2003 |
| 51 Consulting Ltd | Administrative & support | 2025 |
| 51 Creative Limited | Arts & recreation | 2016 |
| 51 CS Limited | Real estate | 2026 |
| 51 Darnley Road (2019) Limited | Households | 2019 |
| 51 Desborough Ltd | Professional & scientific | 2023 |
| 51 Draycott Place Freehold Ltd | Real estate | 2021 |
| 51 Dulwich Road Limited | Households | 2002 |
| 51 Eardley Crescent Freehold Company Limited | Households | 2013 |
| 51 Earls Court Square Freehold Limited | Households | 2018 |
| 51 Eastcheap Tenant Limited | Real estate | 2015 |
| 51 Edith Road Limited | Households | 2013 |
| 51 Eglantine Road Management Company Limited | Hospitality | 1991 |
| 51 Endymion Road RTM Company Limited | Households | 2016 |
| 51 Fairfax Road Limited | Hospitality | 2015 |
| 51 Fairholme Road Limited | Households | 2008 |
| 51 Ferme Park Road Ltd | Households | 2022 |
| 51 Ferntower Road Limited | Real estate | 2007 |
| 51 Finborough Road Management Limited | Households | 1998 |
| 51 Finsbury Limited | Real estate | 2013 |
| 51 Gascony Avenue Limited | Households | 2005 |
| 51 Gilbey Road Property Management Ltd | Households | 2025 |
| 51 Gleneagle Road Management Company Limited | Households | 2014 |
| 51 Gloucester Street Limited | Real estate | 1988 |
| 51 Goldney Road (RTM) Company Limited | Households | 2012 |
| 51 Green Street Limited | Households | 2007 |
| 51 Grosvenor Terrace Ltd | Extraterritorial | 2025 |
| 51 Grovelands Road Limited | Real estate | 2006 |
| 51 Harley Street Limited | Health & social care | 2021 |
| 51 Harrington Gardens Management Company Limited | Households | 1987 |
| 51 Heathland Ltd | Real estate | 2026 |
| 51 Highbury Hill Limited | Real estate | 2006 |
| 51 Hormead Road Properties Ltd | Real estate | 2011 |
| 51 Killyon Road Limited | Real estate | 2015 |
| 51 Lady Margaret Road Limited | Real estate | 1996 |
| 51 Lammas Park (Ealing) Residents Company Limited | Other services | 1987 |
| 51 Lampton Road Ltd | Real estate | 2018 |
| 51 Lancaster Road Limited | Extraterritorial | 2008 |
| 51 Lennard Road Freehold Limited | Households | 2007 |
| 51 Lewin Road (Freehold) Limited | Households | 2025 |
| 51 LEX Records Limited | Arts & recreation | 1999 |
| 51 Limited | Professional & scientific | 2025 |
| 51 Lupus Street (Freehold) Limited | Households | 2007 |
| 51 Lytton Grove Limited | Households | 2020 |
| 51 Maberley Road (London) Freehold Limited | Households | 2024 |