| LW London Limited | Wholesale & retail | 2024 |
| Lynk Real Estate Ltd | Real estate | 2022 |
| Lynk Solutions Limited | Information & communication | 2018 |
| Lynkcity Limited | Professional & scientific | 2014 |
| Lyonesse London Ltd | Wholesale & retail | 2020 |
| Lyth Piling & Groundworks Ltd | Construction | 2022 |
| M & H Civils Limited | Construction | 2014 |
| M & L Environmental Ltd | Water & waste | 2025 |
| M & R Heating Ltd | Construction | 2024 |
| M a Clarke & Company Ltd. | Manufacturing | 1987 |
| M a Wakers Electrical Limited | Construction | 2014 |
| M and H Civil Construction Limited | Construction | 2021 |
| M Cars (Essex) Ltd | Wholesale & retail | 2024 |
| M G Phillips Holdings Limited | Real estate | 2016 |
| M Hanif Consultancy Limited | Health & social care | 2024 |
| M M Electrical and Building Services Limited | Construction | 2001 |
| M Ryan Consulting Limited | Professional & scientific | 2013 |
| M S Bagri Ltd | Construction | 2017 |
| M&D Accounting Limited | Professional & scientific | 2019 |
| M&I Construct Ltd | Construction | 2022 |
| M&M Residence Limited | Real estate | 2024 |
| M&M Twins Ltd | Wholesale & retail | 2024 |
| M&Nq Ltd | Wholesale & retail | 2022 |
| M&S Construct Ltd | Construction | 2023 |
| M-U-R Limited | Transport & logistics | 2025 |
| M. O. D Delivery Services Ltd | Transport & logistics | 2025 |
| M.A.E Stays Limited | Households | 2025 |
| M.C Plastering Solutions Ltd | Construction | 2023 |
| M.D.P Construct Ltd | Construction | 2016 |
| M.E.Builders Limited | Construction | 2012 |
| M.Fec Services Ltd | Construction | 2022 |
| M.L Catering Limited | Wholesale & retail | 2018 |
| M.T.L. International Limited | Manufacturing | 2006 |
| M1 Recruitment Limited | Administrative & support | 2025 |
| M15 Limited | Transport & logistics | 2025 |
| M4 Foods and Drinks Ltd | Wholesale & retail | 2023 |
| M4-TRANSLATIONS Ltd | Professional & scientific | 2017 |
| M4CARE Resources Management Services Ltd | Health & social care | 2022 |
| MA Traders 92 Ltd | Wholesale & retail | 2026 |
| MA4 Property Ltd | Real estate | 2025 |
| Maab Solutions Limited | Professional & scientific | 2008 |
| Maan's Lounge Ltd | Hospitality | 2024 |
| MAB Contracting Services Ltd | Administrative & support | 2013 |
| Mabs RMB Ltd | Arts & recreation | 2026 |
| MAC Investment Group Ltd. | Real estate | 2023 |
| Mac-Tos UK Ltd | Wholesale & retail | 2019 |
| Macfoods Ltd | Manufacturing | 2020 |
| Mackay & Williams Ltd | Health & social care | 2023 |
| Macs Cons Ltd | Construction | 2025 |
| Mactethos Ltd | Information & communication | 2020 |
| Madanne Consulting Limited | Professional & scientific | 2019 |
| Madecare Limited | Health & social care | 2019 |
| Madex Ltd | Transport & logistics | 2021 |
| Madhavansh Ltd | Wholesale & retail | 2020 |
| Madhuban (Haslemere) Limited | Hospitality | 2020 |
| Madison Walk (Chafford Hundred) Management Company Limited | Households | 2005 |
| Mads Woodfloor Restoration Ltd | Manufacturing | 2025 |
| Maestro Group Ltd | Construction | 2018 |
| Mafs Trading Ltd | Wholesale & retail | 2026 |
| Maftei Civils Ltd | Construction | 2023 |
| Magic Hammer Ltd | Construction | 2019 |
| Magic MM Limited | Transport & logistics | 2017 |
| Magic Restore Limited | Construction | 2025 |
| Magpie Cooperative Ltd | Wholesale & retail | 2022 |
| Maia Haulage Ltd | Transport & logistics | 2019 |
| Maid to Clean Services Ltd | Administrative & support | 2024 |
| Maihom Limited | Real estate | 2023 |
| Mailing GUY Ltd | Manufacturing | 2008 |
| Maisha&Maliha Ltd | Wholesale & retail | 2025 |
| Maison DE Cosmetics Ltd | Wholesale & retail | 2025 |
| Maiver Ltd | Real estate | 2023 |
| Majan Martin 0685 Limited | Transport & logistics | 2022 |
| Majestic Horizons Ltd | Information & communication | 2025 |
| Majger Ltd | Transport & logistics | 2016 |
| Majient Estates Ltd | Real estate | 2026 |
| Majient Ltd | Information & communication | 2023 |
| Majlen Ltd | Construction | 2026 |
| Major Domicile Ltd | Health & social care | 2017 |
| MAK & PAT Ltd | Transport & logistics | 2017 |
| MAKC-73 Ltd | Construction | 2021 |
| Makegood Services Ltd | Construction | 2019 |
| Mako Haulage Ltd | Transport & logistics | 2019 |
| Makolija Limited | Transport & logistics | 2019 |
| Makpro Care Ltd | Health & social care | 2022 |
| Maks Property Limited | Wholesale & retail | 2022 |
| Mala Transport Ltd | Transport & logistics | 2019 |
| Malbol Ltd | Health & social care | 2023 |
| Malkha Haulage Services Ltd | Transport & logistics | 2025 |
| Malwayi Transport Ltd | Transport & logistics | 2024 |
| Malyar Ltd | Information & communication | 2023 |
| MAM Commercial Limited | Real estate | 2017 |
| Mama G'S Limited | Wholesale & retail | 2023 |
| Mamcarczyk Ltd | Transport & logistics | 2022 |
| MAN Design and Construction Ltd | Construction | 2017 |
| MAN Must Wack Restaurant & Bar Ltd | Hospitality | 2025 |
| Manage My Moves Limited | Manufacturing | 2014 |
| Manak Kitchen Ltd | Hospitality | 2026 |
| Manak Sweet Centre Limited | Hospitality | 2024 |
| Manansukrun Ltd | Manufacturing | 2012 |
| Manchett Group Limited | Administrative & support | 2014 |