| Marquesse Limited | Information & communication | 2001 |
| Marshall Developments Cornwall Ltd | Construction | 2017 |
| Martin Automotive Design Limited | Manufacturing | 2019 |
| Martintina Limited | Financial services | 2021 |
| Matley Electrical & Solar PV Limited | Construction | 2015 |
| Matthews & Sadler Estates Limited | Professional & scientific | 2021 |
| Mauvais Limited | Wholesale & retail | 2021 |
| Maverick Hair Ltd | Wholesale & retail | 2010 |
| Maximum Entertainment UK Limited | Information & communication | 1994 |
| Mayes Creative Limited | Administrative & support | 2019 |
| MB Global Properties Limited | Real estate | 2020 |
| MBD Security Ltd | Administrative & support | 2026 |
| MC Technologies Ltd | Information & communication | 2017 |
| Mclaren Sales and Marketing Limited | Professional & scientific | 2023 |
| Mcmahon International Ltd | Professional & scientific | 2023 |
| MD Lotus Nail Spa Ltd | Other services | 2024 |
| Mdmindfuldating Limited | Information & communication | 2024 |
| Meadows (Fenton) Limited | Wholesale & retail | 1999 |
| Medical & Financial (Holdings) Limited | Financial services | 2024 |
| Melanie Verdejo Properties Limited | Real estate | 2024 |
| MEP Design UK Holdings Limited | Financial services | 2026 |
| Meraki Hair Design Limited | Other services | 2020 |
| Mercury Instruments Limited | Agriculture & fishing | 1992 |
| Mermaid Restaurant Ltd | Hospitality | 2003 |
| Metalex Roofing Limited | Construction | 2007 |
| Metamorfiq Ltd | Extraterritorial | 2023 |
| Meur RAS Developments Ltd | Construction | 2021 |
| MGG Grasmere Limited | Real estate | 2021 |
| MGV Drylining Ltd | Construction | 2022 |
| Michpol Limited | Manufacturing | 2018 |
| Micro Communications (Leeds) Ltd. | Wholesale & retail | 1999 |
| Micro-Analysis Consultants (Refurbishments) Limited | Manufacturing | 2013 |
| Micro-Analysis Consultants Limited | Manufacturing | 1982 |
| Middlemiss Art Ltd | Extraterritorial | 2023 |
| Miley Transport Ltd | Administrative & support | 2018 |
| Millcatt Limited | Financial services | 2013 |
| Millys MOP Cleaning Services Ltd | Administrative & support | 2025 |
| Mint Office Space Limited | Information & communication | 2026 |
| Mira ST Ives Ltd | Hospitality | 2022 |
| Mister Clean Limited | Construction | 1989 |
| MJ Brown Solutions Limited | Information & communication | 2014 |
| MJM Builders (SW) Ltd | Construction | 2002 |
| MJP Construction Limited | Manufacturing | 2019 |
| MK FD Services Ltd | Professional & scientific | 2019 |
| MMX Decorators Limited | Construction | 2019 |
| MN Jones Digger Services Ltd | Agriculture & fishing | 2021 |
| Mocvd Solutions Limited | Professional & scientific | 2006 |
| Mode Architectural Glazing Limited | Construction | 2022 |
| Modular Vans Ltd | Manufacturing | 2022 |
| Monetary Matters Limited | Professional & scientific | 2020 |
| Monkey Park Community Ltd | Mining & quarrying | 2023 |
| Montague Holdings Ltd | Real estate | 2023 |
| Montaz Limited | Hospitality | 2019 |
| Monty Dog Enterprises Ltd | Hospitality | 2024 |
| MOP Stars Ltd | Administrative & support | 2026 |
| Morningstar Information Systems Limited | Information & communication | 1997 |
| Mortality Manifest Limited | Financial services | 2003 |
| Mortgage Savvy Ltd | Financial services | 2019 |
| Mortlock Construction Ltd. | Construction | 1993 |
| Motorcycle Sport and Leisure Tours Limited | Administrative & support | 2000 |
| Motorrad Riders Limited | Other services | 2025 |
| Mountcollins Developments Ltd | Construction | 2021 |
| Move With US Limited | Professional & scientific | 1999 |
| MOVE4PAWS Ltd | Other services | 2024 |
| Moving Made Easy (South East) Limited | Real estate | 2010 |
| Moving Made Easy Holdings Limited | Financial services | 2021 |
| MR & MRS Gareth Brown Limited | Other services | 2014 |
| MR Jaat Transportation Ltd | Transport & logistics | 2026 |
| MR Robert's Painting and Decorating Services Ltd | Construction | 2017 |
| Msmdg Holdings Limited | Real estate | 2016 |
| Msmdg Properties Limited | Construction | 2014 |
| Msmdg Rental Properties Limited | Real estate | 2016 |
| MSR Automotive Ltd | Wholesale & retail | 2026 |
| Munro Phillips & Co Limited | Professional & scientific | 2019 |
| Murt & Navin Electrical Ltd | Construction | 2022 |
| MUS Catering Ltd | Hospitality | 2019 |
| My Global Parcel Limited | Transport & logistics | 2011 |
| My Plan Ltd | Professional & scientific | 2019 |
| My Stay Cambridge Limited | Real estate | 2024 |
| Mybur Enterprises Limited | Hospitality | 2022 |
| N & S Valeting Services Ltd | Administrative & support | 2005 |
| N.Trust Accountancy Limited | Professional & scientific | 2017 |
| NADIRILER27 Ltd | Hospitality | 2026 |
| NAJ Consultancy Ltd | Administrative & support | 2016 |
| Nakshi C.I.C. | Wholesale & retail | 2024 |
| National Car Buyer Limited | Wholesale & retail | 2026 |
| National Construction Training Services Limited | Education | 2016 |
| Nationwide Cardiovascular Limited | Health & social care | 2022 |
| Natnet Ltd | Wholesale & retail | 2016 |
| Natsar Limited | Construction | 2024 |
| Natural SHY Limited | Information & communication | 2010 |
| Nautilus Property Ltd | Hospitality | 2021 |
| Navitech Consultancy Ltd | Information & communication | 2024 |
| NE & KJ Younger Services Ltd | Transport & logistics | 2017 |
| Neblagon Ltd | Information & communication | 2018 |
| Neil O'Connor Ltd | Construction | 2003 |
| Nelsons Butchers Holdings Limited | Wholesale & retail | 2019 |
| Neon Sky Limited | Professional & scientific | 2023 |
| Neurodiversity Plus Limited | Education | 2024 |
| New Arifa Tandoori Ltd | Hospitality | 2019 |