| Limplast Ltd | Other services | 2024 |
| Linda Green Properties Ltd | Real estate | 2015 |
| Lindsell Investments Ltd | Financial services | 2025 |
| Line 2 Solutions Limited | Professional & scientific | 2024 |
| Lingua Camps Ltd | Education | 2024 |
| Linq Life Sciences Ltd | Professional & scientific | 2019 |
| Linton-Bruce Limited | Agriculture & fishing | 2016 |
| Lionhart Properties Ltd | Real estate | 2008 |
| Little Island Legal Ltd | Professional & scientific | 2025 |
| Little Marvels Children's Safeguarding Training Ltd | Education | 2025 |
| Littlechild Aggregates Ltd | Transport & logistics | 2025 |
| Livram Ltd | Other services | 2018 |
| Llamedos Limited | Financial services | 2022 |
| LMB Logistics Ltd | Transport & logistics | 2026 |
| Locked OUT Property Maintenance Limited | Households | 2006 |
| Loconer Ltd | Other services | 2024 |
| Logic Safety Solutions Ltd | Professional & scientific | 2011 |
| Logistics Action Limited | Professional & scientific | 2003 |
| Lomax Estates Ltd | Wholesale & retail | 2017 |
| London Engineering Fabrications Limited | Administrative & support | 1997 |
| London Medical Concierge Limited | Health & social care | 2016 |
| Lone Wolf Comedy Ltd | Arts & recreation | 2026 |
| Longtown Pellets Limited | Manufacturing | 2017 |
| Look Good Easily Motivational Speaking Ltd | Administrative & support | 2018 |
| Lotus House PE19 Ltd | Hospitality | 2023 |
| Louise Savin Designs Ltd | Professional & scientific | 2023 |
| Love Farm Kebab Ltd | Hospitality | 2026 |
| LP Events Ltd | Wholesale & retail | 2021 |
| LP Travel Limited | Administrative & support | 2013 |
| LRS Associates Limited | Wholesale & retail | 1995 |
| LRS Property Holdings Limited | Administrative & support | 2018 |
| Lucerb Construction Limited | Construction | 2018 |
| Lucerb Freeholds Ltd | Real estate | 2020 |
| Lucerb Limited | Real estate | 2016 |
| Luff Interiors Limited | Construction | 2021 |
| Luke Court Residents Company (Eynesbury) Limited | Households | 1987 |
| Lumbis Associates Limited | Professional & scientific | 2008 |
| Lumbis Investments Limited | Real estate | 2021 |
| Lumina Insights Limited | Information & communication | 2024 |
| LUX Shop Plus Ltd | Wholesale & retail | 2025 |
| Luxorite Ltd | Other services | 2023 |
| Luxurioushade Limited | Wholesale & retail | 2025 |
| Lvdon Ltd | Wholesale & retail | 2022 |
| Lyon Access Limited | Construction | 2012 |
| M & B Driveways Limited | Construction | 2014 |
| M & J S Services Ltd | Transport & logistics | 2023 |
| M & M Coloured Rendering & Plastering Limited | Construction | 2025 |
| M & P Thody Ltd | Households | 2022 |
| M G Tree Surgery Limited | Administrative & support | 2021 |
| M I Tickner Decorators Limited | Construction | 2018 |
| M S P Retail Limited | Wholesale & retail | 2002 |
| M Thompson Tree Care Limited | Administrative & support | 2021 |
| M.A.O Transport Consultants Ltd | Transport & logistics | 2026 |
| M3THI Ltd | Hospitality | 2021 |
| Maame Limited | Health & social care | 2014 |
| Maati Tech Technnology Sollution Limited | Information & communication | 2016 |
| Maceagle.Ai Ltd | Professional & scientific | 2025 |
| Madartsoft Ltd. | Information & communication | 2009 |
| Madison's Bar Ltd | Hospitality | 2025 |
| MAG Electrical Services Ltd | Construction | 2018 |
| Magic Angels Ltd | Information & communication | 2020 |
| Magic Detailing Ltd | Wholesale & retail | 2024 |
| Magpie Property Management Limited | Real estate | 2009 |
| Maison Mundi Ltd | Real estate | 2025 |
| Maitland's Coffee Hand Roasters Ltd | Hospitality | 2025 |
| Maja Maifeld Ltd | Administrative & support | 2022 |
| Major Events Consultancy Ltd | Professional & scientific | 2025 |
| Majorcarers PVT Limited | Health & social care | 2023 |
| Mallard Azura Limited | Administrative & support | 2017 |
| Maltepe Limited | Manufacturing | 2000 |
| Managing Change (Cambridge) Limited | Professional & scientific | 2005 |
| Mango Consultants Ltd | Professional & scientific | 2011 |
| Mango Real Estate Ltd | Real estate | 2025 |
| Manyweathers Cider Co Ltd | Wholesale & retail | 2024 |
| March MAY (Holdings) Limited | Professional & scientific | 2013 |
| Margaux Creative Limited | Administrative & support | 2013 |
| Marina Telecom Limited | Information & communication | 2009 |
| Marinova Trading Ltd | Wholesale & retail | 2022 |
| Mark Christopher Properties Limited | Real estate | 2018 |
| Mark Coward Design Ltd. | Manufacturing | 2011 |
| Market Advantage Ltd | Professional & scientific | 2024 |
| Marpan Healthcare Ltd | Public administration | 2022 |
| Marquis Software Limited | Information & communication | 2019 |
| Marshall Estate Management Limited | Other services | 2017 |
| Marshall Window Cleaning Limited | Administrative & support | 2018 |
| Martin Lines Farming and Environmental Services Ltd | Professional & scientific | 2023 |
| Martin Phillips Associates Limited | Professional & scientific | 2002 |
| Martinik Ltd | Other services | 2023 |
| Martony Court Residents Association Limited | Households | 2007 |
| Marturas Limited | Professional & scientific | 2013 |
| Marzar Ltd | Education | 2019 |
| Mason Robertson Ltd | Wholesale & retail | 2023 |
| Masonic Rooms (Eaton Socon) Ltd | Hospitality | 2026 |
| Mass Consultants Limited | Information & communication | 1983 |
| Matt Wheelton International Limited | Transport & logistics | 2019 |
| Matthew Power Photography Limited | Professional & scientific | 2015 |
| Matthew Taylor AV Ltd | Information & communication | 2026 |
| Maven Media Accountants Limited | Professional & scientific | 2015 |
| Maxbid Group Limited | Information & communication | 2026 |
| Mayday Consultants Ltd | Professional & scientific | 2022 |