| Mobc Limited | Administrative & support | 2015 |
| Mobhex Ltd | Wholesale & retail | 2023 |
| Mobiam Limited | Professional & scientific | 2024 |
| Mobile Professional Tyres Ltd | Wholesale & retail | 2024 |
| Mobile Welders Commercial and Domestic UK Ltd | Professional & scientific | 2024 |
| Mobiles FIX Ltd | Wholesale & retail | 2018 |
| Mobility Deliveries Limited | Transport & logistics | 2025 |
| Mobius Improvement Limited | Administrative & support | 2015 |
| Moby Limited | Information & communication | 2016 |
| Moc-Phs Limited | Construction | 2026 |
| Mocha Magic Ltd | Hospitality | 2025 |
| Mococo Mold Limited | Wholesale & retail | 2019 |
| Modaheat Ltd | Wholesale & retail | 2026 |
| Modcomms Limited | Information & communication | 2009 |
| Mode 4 Consultancy Limited | Professional & scientific | 2023 |
| Modern Auto Solutions Ltd | Wholesale & retail | 2019 |
| Modern Day Funerals Ltd | Other services | 2019 |
| Modern Software Limited | Information & communication | 2021 |
| Modus Hopper & I Ltd | Other services | 2019 |
| MOE Miah Ltd | Professional & scientific | 2018 |
| Moeller & Poeller Engineering Ltd | Professional & scientific | 2013 |
| Moffat Finance Limited | Financial services | 2012 |
| Mohawk Professional Services Ltd | Professional & scientific | 2024 |
| Mohini Property Limited | Real estate | 2019 |
| Mohtrice Limited | Health & social care | 2025 |
| MOI Hope Ltd | Construction | 2018 |
| Moisii Trans Ltd | Transport & logistics | 2019 |
| Mojo Innovations Ltd | Wholesale & retail | 2020 |
| Molave Limited | Real estate | 2025 |
| Moll Transport Ltd | Transport & logistics | 2024 |
| Moller Engineering Limited | Professional & scientific | 2016 |
| Mollies Bar Limited | Hospitality | 2020 |
| Molloy Software Limited | Information & communication | 2017 |
| Molyneux Design Services Ltd | Professional & scientific | 2019 |
| Momentum Engineering Services Ltd | Manufacturing | 2024 |
| Momoga Limited | Transport & logistics | 2019 |
| MON Abri Ventures Limited | Information & communication | 2018 |
| Mona 2003 Ltd | Transport & logistics | 2026 |
| Monarc Hire Ltd | Administrative & support | 2026 |
| Money and ME Solicitors Limited | Professional & scientific | 2020 |
| Money Carer Services Limited | Financial services | 2019 |
| Monia's Cakes Limited | Manufacturing | 2021 |
| Monk Procurement Limited | Administrative & support | 2025 |
| Monk Sports Holdings Ltd | Administrative & support | 2025 |
| Monkbear Limited | Information & communication | 2020 |
| Monochrome Research and Evaluation Ltd | Professional & scientific | 2023 |
| Monopol Construction Ltd | Construction | 2018 |
| Monotastic Limited | Administrative & support | 2004 |
| Mons Advertising Services Ltd | Professional & scientific | 2019 |
| Monsieur Cheveau Limited | Information & communication | 2018 |
| Montaro Property Group Limited | Real estate | 2026 |
| Monteiro & Alvarenga Limited | Transport & logistics | 2020 |
| Montpellier Investments (North West) Limited | Administrative & support | 2024 |
| Montray Ltd | Hospitality | 2024 |
| Monuk Property Limited | Construction | 2025 |
| Monwol Ltd | Wholesale & retail | 2022 |
| Monza Group Ltd | Wholesale & retail | 2023 |
| Moodified Consulting Ltd | Administrative & support | 2025 |
| Moomoo Trading Limited | Wholesale & retail | 2024 |
| Moon Executive Travels Ltd | Transport & logistics | 2024 |
| Mooncroft Consult Ltd | Administrative & support | 2025 |
| Moonfli Software Solutions Limited | Information & communication | 2012 |
| Moonlight Marketing & Media Ltd | Professional & scientific | 2022 |
| Moonshine Investment Holdings Limited | Financial services | 2020 |
| Moore Aviation Training Services Ltd | Professional & scientific | 2019 |
| Moore Business Solutions Ltd | Professional & scientific | 2025 |
| Moore Construction (Cheshire) Limited | Construction | 2018 |
| Moore Estimating Services Ltd | Administrative & support | 2025 |
| Moore Financial Management Ltd | Professional & scientific | 2009 |
| Moore Jackson Ltd | Wholesale & retail | 2024 |
| Moore Management Solutions Ltd | Administrative & support | 2023 |
| Moore Plants Limited | Agriculture & fishing | 2014 |
| Moorland Steel Limited | Administrative & support | 2025 |
| Moose Quality Services Limited | Administrative & support | 2015 |
| Mootis Limited | Professional & scientific | 2014 |
| MOR Inns (Holdings) Ltd | Financial services | 2026 |
| MOR Inns Austins Ltd | Hospitality | 2026 |
| MOR Inns Group Ltd | Hospitality | 2024 |
| MOR Inns Porters Ltd | Hospitality | 2026 |
| Moran's Wood Components Ltd | Manufacturing | 2006 |
| Moraru Driving Ltd | Transport & logistics | 2017 |
| More Pubs Ltd | Real estate | 2014 |
| More Than Speech Therapy Limited | Health & social care | 2017 |
| More Than Together CIC | Health & social care | 2025 |
| More Volume Design Limited | Administrative & support | 2023 |
| Moretti Holdings Ltd. | Real estate | 2023 |
| Morgan Branding Limited | Professional & scientific | 2017 |
| Morgan Consultancy & Communication Limited | Professional & scientific | 2017 |
| Morgan Williams Commercial LLP | | 2005 |
| Morganash Systems Limited | Information & communication | 2025 |
| Morliwell Limited | Administrative & support | 2006 |
| Morph Architecture Limited | Professional & scientific | 2009 |
| Morphosa Ltd | Other services | 2002 |
| Morphous Design Limited | Professional & scientific | 2018 |
| Morphy Richards Appliances Limited | Financial services | 1982 |
| Morphy Richards Limited | Extraterritorial | 1959 |
| Morris-Motive Limited | Administrative & support | 2025 |
| Morrismoh Ltd | Administrative & support | 2013 |
| Morrisnrg Ltd | Energy | 2022 |
| Morse Business Software Ltd | Information & communication | 2019 |