| Motion Interactive Limited | Information & communication | 2026 |
| Motive Creative Ltd | Professional & scientific | 2023 |
| Motor Oils Limited | Wholesale & retail | 2026 |
| Moulton Consortium Ltd | Financial services | 2015 |
| Moulton Houses Limited | Real estate | 2010 |
| Mountgate Properties Ltd | Real estate | 2023 |
| Mouse Developing Ltd | Construction | 2016 |
| Movememedia Ltd | Professional & scientific | 2021 |
| Moving Direct Ltd | Transport & logistics | 2019 |
| Moving Memory Films Ltd | Information & communication | 2022 |
| Moxie Unleashed Ltd | Health & social care | 2022 |
| MP Auto Services Ltd | Wholesale & retail | 2023 |
| Mp&J Dental Limited | Health & social care | 2022 |
| Mp&J Properties Ltd | Real estate | 2019 |
| MP2 Environmental Limited | Professional & scientific | 2003 |
| Mpgg Ltd | Real estate | 2024 |
| MPK Traders Limited | Wholesale & retail | 2024 |
| MPM Lighting Limited | Wholesale & retail | 2025 |
| MR Aerosol Ltd | Wholesale & retail | 2014 |
| MR E Investments Ltd | Real estate | 2023 |
| MR E Trustees Ltd | Real estate | 2021 |
| MR Floor Commercial Ltd | Wholesale & retail | 2024 |
| MR Floor Sussex Ltd | Wholesale & retail | 1996 |
| MR Installations Limited | Construction | 2009 |
| MR Sparkle Ashford Ltd | Administrative & support | 2025 |
| MRF Holdings Ltd | Construction | 2017 |
| MRL Consulting Group Limited | Administrative & support | 1997 |
| MRL Contracting & Interim Solutions Ltd | Administrative & support | 2004 |
| Mrsn Ltd | Wholesale & retail | 2019 |
| MS Export Global Ltd | Wholesale & retail | 2025 |
| MS Management Consultants Ltd | Construction | 2018 |
| MSA Law (Litigation Management) Limited | Professional & scientific | 2015 |
| Mskk Medical Limited | Health & social care | 2022 |
| MSM Burgers Ltd | Hospitality | 2021 |
| Msquare Consultants Limited | Professional & scientific | 2025 |
| MSS Locums Ltd | Health & social care | 2015 |
| MST Dental Limited | Health & social care | 2022 |
| MST Education and Training Limited | Professional & scientific | 2020 |
| Msukumo Ltd | Professional & scientific | 2014 |
| Mtaslanturk Ltd | Wholesale & retail | 2025 |
| MTD Britain Ltd | Administrative & support | 2025 |
| MTK Design LLP | | 2018 |
| Mudhut Property Limited | Information & communication | 2012 |
| Mulberry Flooring Agency Limited | Wholesale & retail | 2009 |
| Mulholland (Hove) Limited | Wholesale & retail | 2003 |
| Mulutesfa CIC | Wholesale & retail | 2021 |
| Mum's Cleaning Co. Ltd | Administrative & support | 2016 |
| Munros Services Limited | Transport & logistics | 2024 |
| Muoviculo Ltd | Wholesale & retail | 2026 |
| Muraa Ltd | Professional & scientific | 2026 |
| Murasaki Limited | Hospitality | 2003 |
| Murewa Investments Limited | Real estate | 2009 |
| Murphy Bidco Limited | Professional & scientific | 2020 |
| Murphy Debtco Limited | Professional & scientific | 2020 |
| Murphy Midco Limited | Professional & scientific | 2020 |
| Murphy Therapeutic Services Ltd | Health & social care | 2023 |
| Murphy Topco Limited | Professional & scientific | 2020 |
| Murrell Film Services Limited | Information & communication | 2006 |
| Murtaza Naseem Ltd | Information & communication | 2019 |
| Museum Coffeeshop Limited | Hospitality | 2013 |
| Music Art People Ltd | Hospitality | 2025 |
| Mustafa Digital Limited | Wholesale & retail | 2025 |
| Mutare Properties Limited | Real estate | 2009 |
| Muzzall & Co Ltd | Real estate | 2013 |
| MVC Contractor Ltd | Information & communication | 2012 |
| MVG Electrical Services Ltd | Construction | 2021 |
| Mvuma Properties Limited | Real estate | 2009 |
| MW Communications Ltd | Professional & scientific | 2023 |
| MW Football Consultancy Ltd | Arts & recreation | 2025 |
| MWK IT Solutions Limited | Information & communication | 2009 |
| MXS Consultancy Limited | Information & communication | 2025 |
| My Atlas Private Travel Ltd | Administrative & support | 2024 |
| My Buildings Ltd | Real estate | 2020 |
| My FAB Guest Ltd | Hospitality | 2019 |
| My FAB House Ltd | Hospitality | 2019 |
| My Future Champion Limited | Arts & recreation | 2023 |
| My Household Assistant Ltd | Households | 2016 |
| My Networking Club Limited | Other services | 2012 |
| My Private GP Limited | Health & social care | 2025 |
| My Smile Space Limited | Wholesale & retail | 2025 |
| My Wood Flooring Limited | Wholesale & retail | 2021 |
| Mybusiness Technology Limited | Information & communication | 2024 |
| Mycogrowtech Limited | Manufacturing | 2025 |
| Mycology Press Ltd | Information & communication | 2013 |
| Mycominder Ltd | Manufacturing | 2025 |
| Mycor Property Developments Ltd | Real estate | 2018 |
| Mycrogrid Ltd | Professional & scientific | 2024 |
| Mygroup Services Ltd | Administrative & support | 2020 |
| Mypm Ltd | Real estate | 2013 |
| Mysocialworksolution Ltd | Health & social care | 2025 |
| N Square Home Automation Ltd | Construction | 2026 |
| N.O.A Arts Ltd | Arts & recreation | 2023 |
| Nader B Investments Ltd | Financial services | 2026 |
| Nairne Ltd | Professional & scientific | 2023 |
| Nansen Road Management Company Limited | Households | 2001 |
| Nash Property (Brighton) Ltd | Construction | 2023 |
| Nasone Limited | Administrative & support | 2006 |
| Natalie Stone Lettings Ltd | Real estate | 2024 |
| Nationwide Smart Repairs Limited | Wholesale & retail | 2000 |
| Natural Beauty Brains Ltd | Extraterritorial | 2021 |