| 12 Alkham Road Management Company Limited | Extraterritorial | 2012 |
| 12 ALL Saints Road Limited | Hospitality | 2023 |
| 12 Amity Grove Freehold Ltd | Real estate | 2024 |
| 12 Apostilles Ltd | Other services | 2025 |
| 12 Avenue Road (Management) Limited | Households | 1988 |
| 12 Barnsbury Park Limited | Real estate | 2022 |
| 12 Beatrice Road Limited | Households | 2009 |
| 12 Beaumont Road Management Company Limited | Households | 2023 |
| 12 Bennett Park (Freehold) Limited | Households | 2024 |
| 12 Bisham Gardens Limited | Households | 1968 |
| 12 Bloom Park Road Limited | Real estate | 2012 |
| 12 Bloomsbury Square Limited | Other services | 2009 |
| 12 Boswell Place Ltd | Real estate | 2025 |
| 12 Bramham Gardens Limited | Households | 2002 |
| 12 Bridge Close Limited | Professional & scientific | 2016 |
| 12 Bruce Grove Freehold Limited | Households | 2017 |
| 12 Bucks Ltd | Real estate | 2025 |
| 12 Burlington Road Freehold Limited | Households | 2009 |
| 12 Cable Street Limited | Wholesale & retail | 2018 |
| 12 Calthorpe Street Limited | Real estate | 2008 |
| 12 Cambridge Street Management Company Limited | Households | 1999 |
| 12 Capital Ltd | Extraterritorial | 2012 |
| 12 Carlton Road Limited | Households | 1999 |
| 12 Castellain Road Management Company Limited | Households | 1988 |
| 12 Cato Road Management Limited | Households | 2023 |
| 12 Charteris Road Freehold Limited | Households | 2017 |
| 12 Christ Church Road Management Limited | Households | 2013 |
| 12 Coleherne Road Limited | Households | 2013 |
| 12 Colyton Road Limited | Households | 2025 |
| 12 Compton Terrace Limited | Real estate | 2016 |
| 12 Comyn Road Residents Limited | Professional & scientific | 2015 |
| 12 Concanon Road Limited | Households | 2025 |
| 12 Connaught Place Ltd | Households | 2025 |
| 12 Conway Street Management Company Limited | Professional & scientific | 1982 |
| 12 Coolhurst Road Ltd | Households | 2021 |
| 12 Coopers Lane Limited | Households | 2018 |
| 12 Corners Ltd | Hospitality | 2026 |
| 12 Cornwall Gardens Limited | Households | 2003 |
| 12 Corrance Road RTM Company Limited | Households | 2010 |
| 12 Coychurch Road Management Company Ltd | Households | 2022 |
| 12 Crediton Hill Freehold Limited | Households | 2005 |
| 12 Crossley Street Freehold Limited | Households | 2025 |
| 12 Culford Gardens Limited | Households | 2013 |
| 12 Dagmar Road London Limited | Hospitality | 1988 |
| 12 Dagnall Park Freehold Limited | Households | 2026 |
| 12 Daleham Gardens (N.W.3.) Limited | Real estate | 1997 |
| 12 Darlaston Road Residents Limited | Households | 1981 |
| 12 Deacon Road (Freehold) Limited | Households | 2017 |
| 12 Degree Tilt Ltd | Wholesale & retail | 2023 |
| 12 Degrees East Gaming Ltd | Extraterritorial | 2015 |
| 12 Delamere Road Residents Association Limited | Households | 1997 |
| 12 Digby Crescent Limited | Households | 2008 |
| 12 Dishes Catering Ltd | Hospitality | 2025 |
| 12 Drinks a Year Ltd | Hospitality | 2022 |
| 12 DRY Cleaners Ltd | Other services | 2012 |
| 12 Dulwich Road (Freehold) Limited | Households | 2018 |
| 12 Durham Terrace Limited | Households | 2000 |
| 12 Dyne Road Limited | Administrative & support | 2009 |
| 12 Earls Court Square (Management) Limited | Households | 1999 |
| 12 Eccleston Square Limited | Households | 1996 |
| 12 Edith Grove Residents Company Limited | Households | 1999 |
| 12 Edith Terrace Limited | Real estate | 2004 |
| 12 Elements Ltd | Financial services | 2024 |
| 12 ELM Grove Limited | Real estate | 2019 |
| 12 Elmers END Road Management Company Ltd | Households | 2019 |
| 12 England's Lane LLP | | 2013 |
| 12 Episodes Ltd. | Education | 2023 |
| 12 Esmond Road Freehold Limited | Households | 2007 |
| 12 Ethelbert Road RTM Company Limited | Households | 2009 |
| 12 Fairmount Road Limited | Households | 2012 |
| 12 Fawcett Street Residents Limited | Households | 1994 |
| 12 Ferndale Limited | Real estate | 2015 |
| 12 Flags Capital Limited | Other services | 2020 |
| 12 Flags Global Limited | Financial services | 2025 |
| 12 Fortess Road RTM Company Limited | Households | 2015 |
| 12 Gascony Avenue (Management Company) Limited | Households | 2022 |
| 12 Geoffrey Road Residents Company Limited | Households | 2002 |
| 12 Gledhow Gardens Management Ltd | Households | 2002 |
| 12 Gloucester Terrace Ltd | Real estate | 2025 |
| 12 Godman Road Limited | Real estate | 2008 |
| 12 Grafton Square Management Company Limited | Households | 2012 |
| 12 Graham Road Management Company Limited | Households | 2018 |
| 12 Greencroft Gardens Limited | Households | 1998 |
| 12 H H S Car Park Limited | Transport & logistics | 2023 |
| 12 Hales Street RTM Company Limited | Households | 2017 |
| 12 Hampshire Terrace RTM Company Limited | Households | 2025 |
| 12 Handforth Road Freehold Company Limited | Households | 2021 |
| 12 Haus Ltd | Other services | 2025 |
| 12 HAY Hill Ltd. | Real estate | 2014 |
| 12 Healey Street Limited | Households | 2010 |
| 12 Heath Road Ltd | Real estate | 2020 |
| 12 Heathfield Road Tenants Limited | Households | 2000 |
| 12 Herbert Road Ltd | Real estate | 2019 |
| 12 Herndon Road Limited | Professional & scientific | 2003 |
| 12 Hertford Road Management Company Limited | Households | 1997 |
| 12 Hollycroft Avenue Freehold Limited | Real estate | 2010 |
| 12 Holmbush Road Limited | Extraterritorial | 2003 |
| 12 Hornton Street Limited | Real estate | 2006 |
| 12 Hubbard Road (London) Limited | Households | 2014 |
| 12 Hugh Street SW1 Freehold Limited | Households | 2016 |