| LMA Technical Solutions Ltd | Professional & scientific | 2025 |
| LML Project Services Ltd | Professional & scientific | 2011 |
| LOB Construction Limited | Construction | 2018 |
| Lock Marina (Upware) Ltd | Arts & recreation | 1996 |
| Locoespresso (ELY) Limited | Wholesale & retail | 2019 |
| Locoespresso (Witham) Limited | Wholesale & retail | 2019 |
| Locoespresso UK Limited | Wholesale & retail | 2026 |
| Locus Services Limited | Administrative & support | 2019 |
| Lofts Property and Trading Limited | Real estate | 1958 |
| Logistics Partners Consultancy Limited | Professional & scientific | 2019 |
| Lollipops & Lovehearts Ltd | Wholesale & retail | 2024 |
| Longfield Commercial Vehicles Ltd | Wholesale & retail | 2022 |
| Looklikebuyit Ltd | Wholesale & retail | 2026 |
| Lord Groundworks Services Ltd | Construction | 2018 |
| Lords Travel Ltd | Transport & logistics | 2015 |
| Lose the Label CIC | Education | 2014 |
| Lottie & Poddy Ltd | Wholesale & retail | 2025 |
| Loubelle Limited | Financial services | 2025 |
| Love LAB Ltd | Information & communication | 2020 |
| Love Lane by ABI Ltd | Wholesale & retail | 2022 |
| Loveario Ltd | Information & communication | 2025 |
| Lovelace Games Ltd | Manufacturing | 2026 |
| LOW Tipalt Farm Limited | Agriculture & fishing | 2016 |
| Lower Reule Bidco Limited | Financial services | 2017 |
| Lower Reule Bioenergy Limited | Energy | 2008 |
| Lowes Plumbing Heating and Electrical Ltd | Construction | 2017 |
| Lowings Transport Limited | Wholesale & retail | 2020 |
| Loyal Reliance Services Ltd | Administrative & support | 2020 |
| LP Grocers & Butchers Limited | Wholesale & retail | 2023 |
| Ltd Agri Services Limited | Extraterritorial | 2021 |
| LTP Fish Ltd | Hospitality | 2025 |
| Lucky Lane Management Ltd | Households | 2021 |
| Lucy's Developments Limited | Construction | 2022 |
| Lucyglashes.Beauty Limited | Other services | 2024 |
| Luke Charles Limited | Administrative & support | 2009 |
| Luke Prior Livery Limited | Other services | 2025 |
| Lulu Catering Limited | Hospitality | 2017 |
| Lumina Expert Services Ltd | Professional & scientific | 2025 |
| Luna Skin & Aesthetics Ltd | Health & social care | 2025 |
| Lupincharm Property Management Limited | Other services | 2001 |
| Luxona Ltd | Professional & scientific | 2023 |
| Luxury Sleuth Limited | Hospitality | 2018 |
| Lynn Road Gardens ELY Management Limited | Administrative & support | 2008 |
| Lynn Road Management Limited | Households | 2007 |
| Lynne Hitchin Acupuncture Ltd. | Health & social care | 2013 |
| Lynton Property Investments Ltd | Real estate | 2020 |
| Lyons Languages Ltd | Professional & scientific | 2019 |
| M a C Construction (EA) Ltd | Construction | 2016 |
| M a Rental Ltd | Real estate | 2025 |
| M Evans Landscapes Limited | Administrative & support | 2022 |
| M Frost Farming Ltd | Agriculture & fishing | 2024 |
| M J Driver Construction Limited | Construction | 2002 |
| M J Webb Associates Limited | Information & communication | 2003 |
| M Lane Construction Limited | Construction | 2023 |
| M Russell & SON Design & Build Ltd | Financial services | 2025 |
| M Russell Design and Build Limited | Construction | 2006 |
| M&D Delivery Services Ltd | Transport & logistics | 2026 |
| M&D LTU Limited | Wholesale & retail | 2012 |
| M&T Molloy Limited | Construction | 2014 |
| M. D. Anthony (Holdings) Ltd | Financial services | 2003 |
| M. E. Transport Ltd | Transport & logistics | 2013 |
| M.A.D Invest Limited | Agriculture & fishing | 2023 |
| M.D. Anthony Limited | Construction | 1977 |
| Machshev Consulting Ltd | Information & communication | 2024 |
| Macka Limited | Hospitality | 2024 |
| Made by MUM Ltd | Manufacturing | 2025 |
| Magpie Toys Limited | Wholesale & retail | 2023 |
| Mahendar Bhat Limited | Health & social care | 2025 |
| Mahmudo Ltd | Hospitality | 2023 |
| Mahonia Software Ltd | Information & communication | 2024 |
| Mail Order Trees Ltd | Agriculture & fishing | 2025 |
| Mainspar Ltd | Information & communication | 2016 |
| Mair Development Ltd | Professional & scientific | 2020 |
| Maison Furniture Group Ltd | Wholesale & retail | 2010 |
| Majestic Smile Limited | Health & social care | 2011 |
| Majic Consulting Ltd | Professional & scientific | 2026 |
| Make Building Solutions Limited | Construction | 2019 |
| Maktronix Ltd | Wholesale & retail | 2026 |
| Malloy's Craft Butchery 2 Ltd | Wholesale & retail | 2002 |
| Malloy's Craft Butchery Limited | Hospitality | 2019 |
| Maltby Construction Ltd | Construction | 2020 |
| MAM Tiling Ltd | Construction | 2014 |
| Management 16 Company Limited | Real estate | 2010 |
| Management Assist (West) Ltd | Professional & scientific | 2004 |
| Mandinian Flat Management Company Limited | Households | 1977 |
| Manit Construction Limited | Construction | 2023 |
| Mann Built Ltd | Construction | 2021 |
| Mannys Marketing Ltd | Professional & scientific | 2022 |
| Manor Farm (Mepal)Road Management Company Ltd | Households | 2024 |
| Manor Farm Developments (Coveney) Limited | Construction | 2017 |
| Manor Farm Willingham Ltd | Agriculture & fishing | 2023 |
| Mapa Motors Ltd | Wholesale & retail | 2026 |
| Maple Construction (ELY) Limited | Construction | 2023 |
| Marblelane Limited | Agriculture & fishing | 2000 |
| March Electrical Supplies Limited | Wholesale & retail | 2014 |
| Mare Nava Ltd | Wholesale & retail | 2023 |
| Maria French Development Limited | Construction | 2022 |
| Marius Perfect Delivery 97 Ltd | Transport & logistics | 2025 |
| Mark a Bennett Plumbing & Heating Services Limited | Construction | 2012 |
| Market Kitchen ELY Limited | Wholesale & retail | 2019 |