| 120B New Acton Lane Limited | Financial services | 2015 |
| 120K Creative Ltd | Professional & scientific | 2020 |
| 121 Abundant Learning Ltd | Education | 2025 |
| 121 Academy Ltd | Education | 2025 |
| 121 Accounting Ltd | Professional & scientific | 2023 |
| 121 Advisory Ltd | Financial services | 2016 |
| 121 Alexandra Road Limited | Real estate | 2018 |
| 121 Alma Road Limited | Real estate | 2025 |
| 121 Beaufort Street RTM Company Ltd | Households | 2011 |
| 121 Bounce Ltd | Arts & recreation | 2017 |
| 121 Capital Advisory Limited | Professional & scientific | 2019 |
| 121 Capital Limited | Financial services | 2018 |
| 121 Charlton Church Lane Limited | Households | 2017 |
| 121 Clapham Common Northside London Limited | Households | 1992 |
| 121 Company Formation Limited | Professional & scientific | 2011 |
| 121 Construction Ltd | Construction | 2025 |
| 121 Consultancy Services Limited | Professional & scientific | 2026 |
| 121 Craven Park Limited | Real estate | 2020 |
| 121 Croydon Road Residents Association Limited | Households | 2006 |
| 121 Denmark Road RTM Company Limited | Households | 2011 |
| 121 Earlsfield Road Management Company Limited | Households | 2023 |
| 121 Elborough Street Limited | Extraterritorial | 2005 |
| 121 Essex Road Limited | Households | 2006 |
| 121 Evering Road RTM Company Limited | Households | 2005 |
| 121 Fashion Limited | Wholesale & retail | 2014 |
| 121 Finborough Road Freehold Limited | Households | 2003 |
| 121 Fonthill Properties Ltd | Construction | 2021 |
| 121 Food Supply Limited | Hospitality | 2010 |
| 121 George Lane Ltd | Households | 2011 |
| 121 Hammersmith Grove Limited | Real estate | 2012 |
| 121 Healthcare Solutions Ltd | Health & social care | 2022 |
| 121 Healthcare Training Solutions Ltd | Health & social care | 2026 |
| 121 Helix Limited | Households | 2013 |
| 121 Holdings Ltd | Administrative & support | 2025 |
| 121 Jobs Limited | Administrative & support | 2015 |
| 121 King Henrys Limited | Households | 2017 |
| 121 Kings Road Limited | Administrative & support | 2006 |
| 121 KPR Management Limited | Real estate | 2021 |
| 121 Mount View Road Limited | Households | 2013 |
| 121 Oakland Block Tenant Management Limited | Households | 2018 |
| 121 Online Ltd | Information & communication | 2021 |
| 121 Partners Limited | Information & communication | 2014 |
| 121 Petherton Road Management Company Limited | Households | 2019 |
| 121 Plum Lane RTM Company Ltd | Households | 2020 |
| 121 Productions Limited | Information & communication | 2019 |
| 121 Properties Group Ltd | Real estate | 2024 |
| 121 ST George's Square Limited | Real estate | 2005 |
| 121 Stephendale Road Freehold Ltd | Households | 2019 |
| 121 Sutherland Avenue Management Limited | Households | 1997 |
| 121 Trinity Road Residents Association Limited | Households | 1990 |
| 121 Wemborough House Limited | Real estate | 2025 |
| 121 Wemborough Road Limited | Real estate | 2020 |
| 121 Wilberforce RD Management Ltd | Households | 2015 |
| 121 Yoga Online Ltd | Arts & recreation | 2021 |
| 121-123 Alderney Street London Limited | Households | 2007 |
| 121-123 Charterhouse Property Management Company Limited | Households | 2000 |
| 121-123 Replingham Freehold Ltd | Real estate | 2021 |
| 121-123 Station Road Hendon (Management) Limited | Real estate | 2008 |
| 121-126 Elmhurst Mansions RTM Company Limited | Real estate | 2013 |
| 121-127 Saunders Ness Road RTM Company Limited | Households | 2022 |
| 121.COLLECTIVE Ltd | Professional & scientific | 2018 |
| 121.SUPPORT Ltd | Information & communication | 2024 |
| 121/123 Northcote Road Management Company Limited | Hospitality | 2006 |
| 121/128 Beaufort Mansions Management Limited | Households | 1982 |
| 121/131 Brownlow Road Management Limited | Households | 1978 |
| 1210 Holdings Ltd | Financial services | 2020 |
| 1210 Solutions Ltd | Administrative & support | 2021 |
| 12103 Design Studio Ltd | Professional & scientific | 2020 |
| 1211 Limited | Professional & scientific | 2012 |
| 1212 Estates Limited | Real estate | 2026 |
| 1212. COM Limited | Professional & scientific | 1998 |
| 121222 Holdco Limited | Wholesale & retail | 2017 |
| 1213 Louvaine Road Limited | Real estate | 2022 |
| 121333 Limited | Wholesale & retail | 2017 |
| 1214 Blomfield Limited | Households | 2021 |
| 1215 Ltd | Administrative & support | 2011 |
| 1218 UK Limited | Information & communication | 2014 |
| 12184574 Limited | Extraterritorial | 2019 |
| 121ABA Ltd | Education | 2026 |
| 121AVIATION Ltd | Professional & scientific | 2022 |
| 121E143LH Ltd | Real estate | 2026 |
| 121GP Limited | Real estate | 2021 |
| 121PRODATA Limited | Administrative & support | 2006 |
| 121ROOMS Ltd | Real estate | 2019 |
| 121SPEED Courier Ltd | Transport & logistics | 2008 |
| 122 & 124 Holmleigh Road RTM Company Limited | Real estate | 2008 |
| 122 Acton Lane Company Limited | Real estate | 2012 |
| 122 Barons Court Road Limited | Other services | 1990 |
| 122 Beaufort Street Limited | Households | 1998 |
| 122 Brondesbury Road Management Limited | Real estate | 2001 |
| 122 Burnt ASH Hill RTM Company Ltd | Households | 2021 |
| 122 Christchurch Road Property Ltd | Real estate | 2016 |
| 122 Cotswold Gardens Management Ltd | Real estate | 2022 |
| 122 Drakefell Road Limited | Extraterritorial | 2009 |
| 122 Finborough Road Management Limited | Real estate | 2004 |
| 122 Gloucester Avenue Limited | Households | 2008 |
| 122 Group Ltd | Wholesale & retail | 2021 |
| 122 Hewitt Road Freehold Limited | Households | 2005 |
| 122 Ideas Ltd | Information & communication | 2020 |
| 122 Knollys Road Management Limited | Households | 2015 |