| Little FIN Coffee Roastery Ltd | Hospitality | 2022 |
| Livermore Contracts Limited | Construction | 2010 |
| Living 3 Limited | Construction | 2023 |
| LJ Global Shipping Ltd | Transport & logistics | 2024 |
| Loft Master Limited | Construction | 2001 |
| Lokanta Turkish Restaurant Limited | Hospitality | 2017 |
| Lokenath Food Ltd | Hospitality | 2018 |
| Lolex Solutions Limited | Information & communication | 2012 |
| London & ME Limited | Wholesale & retail | 2017 |
| London Electrical Control Systems Ltd | Construction | 2014 |
| London Law & Land Limited | Financial services | 1987 |
| London Metro Properties Limited | Real estate | 2021 |
| London NW Properties Limited | Real estate | 2018 |
| Lonsdale Therapy Limited | Health & social care | 1996 |
| Louise Road Properties Limited | Construction | 2025 |
| Lovelake Limited | Financial services | 1996 |
| LPC Direct Ltd | Wholesale & retail | 2018 |
| LPH Services Ltd | Construction | 2026 |
| LS Accountancy Services Limited | Professional & scientific | 2011 |
| LSP Design Ltd | Information & communication | 2009 |
| LU BAN Kitchen Foods Ltd | Hospitality | 2022 |
| Lucca Foods Limited | Hospitality | 2007 |
| Lucor Group Ltd | Professional & scientific | 2022 |
| Lucor Property Services Ltd | Real estate | 2022 |
| Luke Christie Maintenance Ltd | Manufacturing | 2025 |
| Lumina Integrated Care Limited | Health & social care | 2013 |
| Luna Transfers Ltd | Transport & logistics | 2025 |
| Lybie Property Limited | Real estate | 2025 |
| Lymphatics Ltd | Health & social care | 2018 |
| Lyndhurst & Lane Associates Limited | Construction | 2008 |
| Lyndhurst GAS Services Limited | Manufacturing | 2024 |
| M & L Parker Associates Limited | Wholesale & retail | 2019 |
| M a E Building Services Ltd | Administrative & support | 2003 |
| M and J Co Properties Limited | Real estate | 2023 |
| M C Hayes Building Contractors Ltd | Construction | 2013 |
| M H D Group Limited | Construction | 2001 |
| M M Property Services Limited | Real estate | 2000 |
| M Paveley Ltd | Arts & recreation | 2009 |
| M T Auto Limited | Wholesale & retail | 2000 |
| M&A Carpentry & Construction Limited | Construction | 2025 |
| M&A Chambers Ltd | Administrative & support | 2023 |
| M&B Affordable Housing Limited | Real estate | 2024 |
| M.E.L. Health & Safety Consultants Ltd | Health & social care | 1999 |
| M.R.B Construction (Essex) Ltd | Construction | 2018 |
| Mablem Holding Co Limited | Financial services | 2025 |
| Mablem Ltd | Professional & scientific | 2023 |
| Magic Industries Limited | Hospitality | 2020 |
| Magical Mortgages Ltd | Financial services | 2022 |
| Mainpitch Limited | Professional & scientific | 1987 |
| Maisemore Court Farm Energy Centre Limited | Energy | 2020 |
| Maitland Enterprise Rochford Limited | Wholesale & retail | 2011 |
| Makeitembroidered Limited | Manufacturing | 2025 |
| Manley & Co Consulting Limited | Information & communication | 2016 |
| Mannequin Productions Limited | Information & communication | 2019 |
| Mansfield Accounting Limited | Professional & scientific | 2011 |
| Maplin Court Maintenance Company Ltd | Households | 2006 |
| Maplin Developments Limited | Real estate | 2005 |
| Marathon Technology Limited | Information & communication | 1997 |
| Marcello Longevity Limited | Information & communication | 2026 |
| Mark Curnick Building Services Ltd | Construction | 2025 |
| Mark Kelly Tiling Limited | Construction | 2006 |
| Mark One Group Limited | Financial services | 2020 |
| Mark One Hire Limited | Construction | 1988 |
| Market West Coffee Ltd | Hospitality | 2021 |
| Marks Estate Southchurch Avenue Company Limited | Households | 2023 |
| Martin Electrics Limited | Energy | 2015 |
| Master Holmes Ltd | Construction | 2023 |
| Matt OPS Limited | Information & communication | 2017 |
| Maules Finance Ltd | Professional & scientific | 2022 |
| Maurice LEE Secretarial Limited | Professional & scientific | 2005 |
| Maurice's Limited | Construction | 1998 |
| Maven and Moxie Ltd | Professional & scientific | 2025 |
| Maya Horizon Ltd | Real estate | 2025 |
| Mayfair Management (Rental Property) Ltd | Real estate | 2021 |
| Mazmap Consulting Ltd | Professional & scientific | 2026 |
| Mccb Holdings Limited | Financial services | 2021 |
| MCS Microwave Limited | Manufacturing | 2000 |
| MDC Carpentry & Building Limited | Construction | 2012 |
| MDG Suppliers Ltd | Wholesale & retail | 2024 |
| MDH Motors Ltd | Wholesale & retail | 2015 |
| Meads Mosaics Limited | Construction | 2023 |
| Means of Escape Publications Limited | Administrative & support | 2001 |
| Medicus Maximus Limited | Wholesale & retail | 2000 |
| MEI SHI (Ormskirk) Ltd | Hospitality | 2022 |
| Melksham Energy Centre One Ltd | Energy | 2014 |
| Melksham Energy Centre Two Ltd | Energy | 2019 |
| Meon Sure Ltd | Wholesale & retail | 2017 |
| Mercury Sourcing Network Ltd | Wholesale & retail | 2023 |
| Merlin Property Investments Limited | Real estate | 1996 |
| Merlin Property South East Ltd | Real estate | 2023 |
| Meteorwrite Limited | Financial services | 2019 |
| Method IT Limited | Extraterritorial | 2022 |
| Meyers ANP Ltd | Health & social care | 2024 |
| MG Medical Ltd | Health & social care | 2018 |
| Mghs Limited | Administrative & support | 2006 |
| Midland Bronze Ltd | Extraterritorial | 2018 |
| Mike Aldridge Solutions Limited | Information & communication | 2003 |
| Milkframe Limited | Information & communication | 2018 |
| Milton Gate Mews Management Company Limited | Households | 2003 |
| Minerals Property Ltd | Real estate | 2024 |