| Ignite Prime Topco Limited | Financial services | 2024 |
| Iksel Films Ltd | Information & communication | 2018 |
| IN Living Ltd | Real estate | 2025 |
| IN Touch Capital Markets Limited | Financial services | 2003 |
| Inception Worldwide Limited | Construction | 2017 |
| Indus Petroleum Limited | Wholesale & retail | 2017 |
| INFOBANK24 Ltd | Information & communication | 2017 |
| Insight Commercial Services Ltd | Professional & scientific | 2018 |
| Instinctive Audio Ltd | Information & communication | 2013 |
| Integ House Limited | Information & communication | 2025 |
| Integrate Telecommunication Ltd | Information & communication | 2022 |
| Intelligent Spatial Limited | Information & communication | 2026 |
| Inter Car Cleaning Wimbledon Ltd | Administrative & support | 2023 |
| International Trade Consulting Solutions Limited | Professional & scientific | 2015 |
| IT22 Ltd | Information & communication | 2022 |
| ITC Crvm Limited | Financial services | 2013 |
| ITC FX Limited | Financial services | 2013 |
| J&K Investment (UK) Limited | Real estate | 2013 |
| J. J. Park Ltd | Wholesale & retail | 2012 |
| Jacob Street Management Company Limited | Households | 1986 |
| Jaintech Limited | Information & communication | 2015 |
| Jakemans Barbers Ltd | Other services | 2017 |
| Jarvis Stark Group Ltd | Professional & scientific | 2021 |
| Jasunsoft Technologies Limited | Information & communication | 2025 |
| Jawad Holding Limited | Real estate | 2018 |
| JAY BEE Electrical Limited | Construction | 2003 |
| Jayamsai Property Ltd | Real estate | 2019 |
| JCM Locksmiths Limited | Other services | 1975 |
| Jean and Temple Ltd | Wholesale & retail | 2021 |
| Jerk Royale Ltd | Wholesale & retail | 2023 |
| Jincom UK Limited | Information & communication | 2018 |
| Jiva Health (Earlsfield) Limited | Other services | 2012 |
| John Desmond Limited | Construction | 1974 |
| John Morley Associates LLP | | 2010 |
| Jorv Collective Ltd | Financial services | 2025 |
| Jothymed Limited | Health & social care | 2005 |
| JRK Restaurants Ltd | Hospitality | 2019 |
| JRK UK Group Ltd | Wholesale & retail | 2023 |
| JRK UK Properties Ltd | Real estate | 2022 |
| Jrmc Limited | Professional & scientific | 2013 |
| Juliana Custers Ltd | Professional & scientific | 2023 |
| Junior Team Golf Limited | Arts & recreation | 2000 |
| Junkwize Ltd | Water & waste | 2012 |
| Justin Homes (RH) Ltd | Construction | 2021 |
| Justin Homes Britain (Russell Hill Road) Ltd | Real estate | 2019 |
| Justin Homes Britain Ltd | Construction | 2019 |
| Justin James Holdings Limited | Hospitality | 2017 |
| Justin James Hotel Trading Limited | Hospitality | 2017 |
| Jutt HUT Ltd | Wholesale & retail | 2025 |
| JVC Compliance Consultancy Ltd | Professional & scientific | 2016 |
| Kach Investments Limited | Real estate | 2016 |
| Kadence London Limited | Wholesale & retail | 2018 |
| Kalal Real Estate Ltd | Real estate | 2023 |
| Karaj Ltd | Professional & scientific | 2018 |
| Kars Vegas Ltd | Wholesale & retail | 2022 |
| KC Vision Properties Ltd | Real estate | 2020 |
| Kensington Associates London Limited | Professional & scientific | 2016 |
| Kingsley Court Limited | Households | 1994 |
| Kingswood Property Services Ltd | Real estate | 2026 |
| Kjam & AP Property Ltd | Real estate | 2015 |
| Kodiak Developments Limited | Construction | 1999 |
| KS Properties Investment Limited | Real estate | 2026 |
| Kudos Investments Limited | Real estate | 2005 |
| Kvds Finance Ltd | Financial services | 2020 |
| Kyma Consulting Limited | Professional & scientific | 2011 |
| L D Care Limited | Health & social care | 2009 |
| L M Invest Ltd | Real estate | 2026 |
| Laburnum Estates Limited | Real estate | 2021 |
| Lalli Consulting Services Limited | Professional & scientific | 2023 |
| Lalli Corporation Limited | Financial services | 2023 |
| Lalli Properties Limited | Real estate | 2023 |
| Land of Colourful Creatures Ltd | Wholesale & retail | 2024 |
| Landsmart Technologies Ltd | Professional & scientific | 2013 |
| Lashan Digital Limited | Information & communication | 2015 |
| Lavender & Lace Limited | Professional & scientific | 2019 |
| Le'Muria (U.K) Limited | Arts & recreation | 2024 |
| Learent Retail Limited | Wholesale & retail | 2024 |
| Learning Changemakers Limited | Professional & scientific | 2020 |
| Legacy Design Labs Limited | Professional & scientific | 2021 |
| Level 1 Developments Ltd | Construction | 2023 |
| Loncal Estates Limited | Administrative & support | 1989 |
| London Aesthetic Surgeons Ltd | Health & social care | 2024 |
| London College of Wimbledon Ltd | Administrative & support | 2003 |
| London Dietitians Limited | Other services | 2003 |
| London Khan Property Limited | Construction | 2025 |
| London Meditation Ltd | Other services | 2017 |
| London Reoganisation 2024-01 Ltd | Financial services | 2015 |
| London Reoganisation 2024-02 Ltd | Information & communication | 2020 |
| London Sundara Travels Ltd | Administrative & support | 2025 |
| Love Wimbledon Limited | Professional & scientific | 2011 |
| Lozenge Services Ltd | Information & communication | 2015 |
| LPE Services Limited | Professional & scientific | 2007 |
| LYNX2MARKET Ltd | Professional & scientific | 2017 |
| Lyrical Communications Limited | Administrative & support | 2006 |
| M&O Shipping Limited | Wholesale & retail | 2026 |
| M-Eat Biltong Ltd | Wholesale & retail | 2017 |
| M.K. Patel Limited | Wholesale & retail | 1973 |
| Maddi Product Consulting Services Ltd | Information & communication | 2025 |
| MAH Media Ltd | Information & communication | 2014 |
| Maidstill Limited | Real estate | 1996 |