| Kenward Pullen Hastings Limited | Extraterritorial | 2000 |
| Kenward Pullen IT Services Ltd | Information & communication | 2009 |
| Kenward Pullen Limited | Construction | 1991 |
| Kerbcut Ltd | Information & communication | 2026 |
| Kerotec Ltd | Manufacturing | 2020 |
| KGS Diamond UK Ltd | Manufacturing | 1999 |
| Kilimanjaro Experts Ltd | Administrative & support | 2018 |
| Kingsnorth & Clements Limited | Administrative & support | 2001 |
| Kingswell Coachworks Limited | Wholesale & retail | 2011 |
| KIT + Clogs Studio Limited | Wholesale & retail | 2019 |
| Kitchen Table Investments Limited | Financial services | 2022 |
| KNB Property Developments Ltd | Construction | 2022 |
| Knowles Building Contractors Ltd | Construction | 2023 |
| Knowles Construction & Developments Ltd | Construction | 2026 |
| Konstrukt Creative Limited | Arts & recreation | 2015 |
| Kosmos Software Ltd | Information & communication | 2026 |
| L C R Fabrications Ltd | Manufacturing | 2012 |
| L J a Electrical Engineering Limited | Construction | 2007 |
| L&D Design and Build Ltd | Construction | 2019 |
| L&M Holiday Homes Ltd | Hospitality | 2024 |
| Laban Property Maintenance Ltd | Administrative & support | 2021 |
| Lambert's Civil Engineering Ltd | Other services | 2017 |
| Lamberts Property Group Ltd | Real estate | 2026 |
| Land Works Investments Ltd | Construction | 2023 |
| Lassen Court Management Company Limited | Households | 2022 |
| LAZER2 Solar Thermal Ltd | Manufacturing | 2023 |
| Lazy Lets Ltd | Real estate | 2025 |
| LCS Brickwork Ltd | Construction | 2018 |
| LCS Roofing & Cladding Ltd | Construction | 2009 |
| Learningwalks Ltd | Information & communication | 2025 |
| Legal Knowledge Ltd | Information & communication | 2014 |
| LEO Ferenc Scientific Imaging Ltd | Professional & scientific | 2025 |
| Leonati Events Ltd | Hospitality | 2023 |
| LEP Property Investment Limited | Real estate | 2023 |
| LH Private Estates Limited | Construction | 2025 |
| Life With Hope Trust | Other services | 2009 |
| Light Soft Ltd | Information & communication | 2018 |
| Lighthouse Films Limited | Information & communication | 2021 |
| Lining Division Limited | Construction | 2009 |
| Little Battle Cafe Ltd | Hospitality | 2025 |
| Little Fluffy Clouds Limited | Arts & recreation | 2023 |
| LK Governance Services LLP | | 2025 |
| LMJ Sports Coaching Ltd | Education | 2024 |
| London Early Years Advisors' Forum C.I.C. | Education | 2016 |
| Looking Forward Productions Limited | Other services | 1994 |
| Loose Farm Barns Management Company Limited | Households | 1989 |
| Lottie Warren Ltd | Professional & scientific | 2018 |
| Lotusleaf Investments Ltd | Professional & scientific | 2023 |
| Love Play Limited | Wholesale & retail | 2023 |
| Lovelorn and Renegade Ltd | Information & communication | 2024 |
| Lower Gate Glamping Ltd | Hospitality | 2020 |
| LRS Financial Investments Ltd | Information & communication | 2021 |
| LSF (S.E.) Limited | Administrative & support | 2011 |
| LTC Marketing Ltd | Professional & scientific | 2015 |
| LTR Performance Limited | Wholesale & retail | 2022 |
| Lucy Sanctuary Ltd | Health & social care | 2021 |
| Made by Carricks Ltd | Manufacturing | 2019 |
| Maison Morrigan Ltd | Professional & scientific | 2026 |
| Manns Amusements Limited | Other services | 1959 |
| Maple Consultants Limited | Professional & scientific | 2017 |
| Marcel Hirshman Limited | Other services | 2007 |
| Marcus EL Korashy Carpentry Ltd | Construction | 2015 |
| Marcus Rickard Ltd | Administrative & support | 2018 |
| Mardan Court Management Company Limited | Households | 1967 |
| Marinapark AVR Ltd | Wholesale & retail | 2015 |
| Mark Borland Limited | Information & communication | 2007 |
| Mark Dyson Music Ltd | Arts & recreation | 2016 |
| Mark Flay Limited | Information & communication | 2024 |
| Marsh Models Limited | Manufacturing | 2002 |
| Martlet Studio Limited | Information & communication | 2023 |
| Mass Systems Ltd | Information & communication | 2023 |
| Materia Medica International Limited | Professional & scientific | 2007 |
| Mcleod 9 Ltd | Professional & scientific | 2003 |
| Meadow Operations Limited | Administrative & support | 2018 |
| Medical Innovations London Ltd | Manufacturing | 2014 |
| Medical Matters International Ltd | Professional & scientific | 1996 |
| Meeching Place RTM Company Limited | Real estate | 2010 |
| Meghr Ltd | Information & communication | 2025 |
| Merchantmen of Britain Ltd | Wholesale & retail | 2005 |
| Merifield Carpentry & Construction Ltd | Construction | 2018 |
| Merner Group Limited | Financial services | 2025 |
| Merrythought RYE Limited | Hospitality | 2021 |
| Microfish Communications Limited | Information & communication | 2001 |
| Middleton Construction Management Limited | Construction | 2010 |
| Millen Martial Arts Limited | Arts & recreation | 2019 |
| Minnie & Belle Limited | Wholesale & retail | 2026 |
| Miram Court Maintenance Limited | Households | 1969 |
| Mitchell & Mitchell Developments Ltd | Construction | 2020 |
| Mitchell Analytical Ltd | Professional & scientific | 2009 |
| Mitchells Construction & Development Ltd | Construction | 2008 |
| MJH CAD Ltd | Construction | 2024 |
| Ml.Shand Limited | Administrative & support | 2025 |
| Modern Barn Farm Ltd | Agriculture & fishing | 2017 |
| Monolite UK Limited | Manufacturing | 2006 |
| Montauroux Services Limited | Professional & scientific | 2014 |
| Moomin Productions Limited | Information & communication | 2015 |
| Morfeys Removals Limited | Transport & logistics | 2007 |
| Mortgage UN Limited | Financial services | 2025 |
| Mosaic Law Limited | Professional & scientific | 2017 |
| MPH Publishing Limited | Information & communication | 2022 |