| Innovation Dance Studios Limited | Arts & recreation | 2011 |
| Innovative Financial Management Solutions Limited | Professional & scientific | 2016 |
| INO Logistics Ltd | Transport & logistics | 2010 |
| Integrated Facade Solutions Ltd | Construction | 2025 |
| Integrated Services Limited | Wholesale & retail | 2002 |
| Intercontinental OIL Services Ltd | Administrative & support | 2017 |
| International OIL Services Limited | Administrative & support | 2020 |
| International Telecommunications Group Inc. | | 2000 |
| Intuition Ppims Limited | Education | 2003 |
| Invenio Brands Ltd | Professional & scientific | 2025 |
| IPA Brands Ltd | Wholesale & retail | 2005 |
| Ipevo Ltd. | Wholesale & retail | 2013 |
| IQ Motors Limited | Wholesale & retail | 2011 |
| IT 4 Business Limited | Information & communication | 2005 |
| IX Technology Limited | Information & communication | 2008 |
| J & a Creations Ltd | Wholesale & retail | 2025 |
| J&J Asset Holdings Ltd | Real estate | 2025 |
| J. Richards Holdings Ltd | Real estate | 2021 |
| JAI Kosh Limited | Health & social care | 2018 |
| Jason Murray Properties Limited | Real estate | 2016 |
| Jesmond Consultancy Limited | Professional & scientific | 2025 |
| Jessavham Holdings Ltd | Financial services | 2026 |
| Jimacomputing Limited | Information & communication | 2017 |
| JSH Design Limited | Information & communication | 2012 |
| JSK Private Practice Ltd | Health & social care | 2018 |
| K-Spark Energy Ltd | Professional & scientific | 2025 |
| Kaku Foods & Drinks Ltd | Wholesale & retail | 2025 |
| Kani Barbers Ltd | Other services | 2020 |
| Karali Group Limited | Professional & scientific | 2014 |
| Karama Foods Ltd | Wholesale & retail | 2025 |
| Karoti Investments LLP | | 2024 |
| KEW Sinfonia Productions Limited | Arts & recreation | 2023 |
| Key Complete Ltd | Administrative & support | 2021 |
| Kinchgate Limited | Professional & scientific | 1982 |
| Kosheli Nepali Cultural Fusion UK | Health & social care | 2012 |
| KSM Creative Solutions Ltd | Wholesale & retail | 2023 |
| Kupa MG Ltd | Real estate | 2024 |
| L B Leisure Group Ltd | Hospitality | 2015 |
| L&N Aesthetic Ltd | Other services | 2025 |
| L1P Ltd | Other services | 2018 |
| Laepel Building and Maintenance Limited | Administrative & support | 2022 |
| Laffayette Electrical Limited | Construction | 2003 |
| Languages Plus Limited | Professional & scientific | 1991 |
| Lash Amour Beauty Ltd | Other services | 2021 |
| Lazbeth Properties Ltd | Construction | 2010 |
| Lcuk Ealing Broadway Limited | Other services | 2018 |
| Learn-Perform-Excel (UK) Ltd | Information & communication | 2012 |
| LED Factory Limited | Construction | 2010 |
| Leep Creative Solutions Ltd | Information & communication | 2023 |
| Lemelston Limited | Households | 1985 |
| Leon Products Ltd | Wholesale & retail | 2025 |
| LFZ Limited | Other services | 2020 |
| LIGHTSEVENTY5 Ltd. | Information & communication | 2013 |
| Ligo Properties Ltd | Real estate | 2019 |
| Lill Architects Limited | Professional & scientific | 2012 |
| Lily Myers Limited | Real estate | 1951 |
| Linda Ellard Limited | Professional & scientific | 2012 |
| LM Global (Holdings) Ltd | Financial services | 2024 |
| Lnpr Properties Ltd | Administrative & support | 2010 |
| Lntm Limited | Financial services | 2023 |
| Locksmith Security Solutions Ltd | Administrative & support | 2023 |
| Locomote Properties Ltd | Hospitality | 2013 |
| Lojan Limited | | 1979 |
| London Beauty Lounge Ealing Limited | Other services | 2025 |
| London Bridge Books Limited | Wholesale & retail | 2015 |
| London Heart Clinic Limited | Health & social care | 2016 |
| London Management Consultancy Services Ltd | Other services | 2020 |
| London PCO Car Rentals Ltd | Administrative & support | 2021 |
| London Spacelet Ltd | Real estate | 2015 |
| London West Ltd | Financial services | 2018 |
| Lorclon Services Limited | Construction | 2007 |
| Luke Hull Limited | Information & communication | 2016 |
| Luke Hull Property Limited | Real estate | 2023 |
| Lutomamill Ltd | Real estate | 2024 |
| LUX Management London Ltd | Professional & scientific | 2025 |
| M a F O Consulting Limited | Professional & scientific | 2011 |
| M J Builders (London) Ltd | Construction | 2019 |
| M&N Solicitors Ltd | Professional & scientific | 2018 |
| M-Felix Holdings Ltd | Financial services | 2025 |
| M4 Investment Ltd | Professional & scientific | 2024 |
| Maakhir Solution Limited | Real estate | 2014 |
| Madmikes Ltd | Wholesale & retail | 2024 |
| Magari Construction Ltd | Construction | 2023 |
| MAI Events Ltd | Professional & scientific | 2024 |
| Major Oak Consultancy Limited | Professional & scientific | 2016 |
| Make IT Ealing Limited | Administrative & support | 2005 |
| Maltwalk Limited | Households | 2001 |
| Manhattan Assets NO 9 Limited | Real estate | 2005 |
| Manhattan Place Limited | Real estate | 2019 |
| Manopa Ltd | Real estate | 2021 |
| Mardn.Com Ltd | Real estate | 2010 |
| Marketing and Branding Ltd | Wholesale & retail | 2011 |
| Marketing Intelligence Services Limited | Professional & scientific | 1992 |
| Mass Law Limited | Professional & scientific | 2022 |
| Matteo Cinti Ltd | Arts & recreation | 2023 |
| Mawlo Ltd | Information & communication | 2015 |
| Maximus Hotels Limited | Hospitality | 2021 |
| MAY I Help U Ltd | Wholesale & retail | 2012 |
| Maykin Financial Consultancy Limited | Construction | 2017 |
| Mcdade Complete Kitchens and Bathrooms Limited | | 1984 |