| Mjuk Limited | Other services | 2017 |
| MJW Associates Limited | Real estate | 2005 |
| MK Deore Clinics Ltd | Health & social care | 2022 |
| MK Marketing (MCR) Ltd | Professional & scientific | 2024 |
| MKA Marketing Ltd | Professional & scientific | 2025 |
| MKD Consulting Limited | Information & communication | 2002 |
| MKD Holdco Limited | Financial services | 2024 |
| MKG Treasury Services Limited | Professional & scientific | 2024 |
| MKH Consultants Limited | Professional & scientific | 2020 |
| MKJ Concepts Limited | Wholesale & retail | 2021 |
| MKK Consulting Ltd | Other services | 2019 |
| Mklh Medical Limited | Health & social care | 2023 |
| MKM IT Projects Limited | Information & communication | 2021 |
| MKR Group Holdings Ltd | Real estate | 2024 |
| Mkvs Property Investments Ltd | Real estate | 2026 |
| ML AI Systems Ltd | Information & communication | 2025 |
| ML Design Services Limited | Administrative & support | 2015 |
| ML Gurney Ltd | Real estate | 2017 |
| ML Home Care Limited | Financial services | 2025 |
| ML Safety Services Limited | Professional & scientific | 2022 |
| MLB Ventures Ltd | Real estate | 2022 |
| MLG Consultancy Ltd | Professional & scientific | 2023 |
| MLP Law Limited | Professional & scientific | 2016 |
| MM & M Consultants Limited | Administrative & support | 2015 |
| MM (Manchester) Limited | Real estate | 2010 |
| MM Malkiat Limited | Real estate | 2021 |
| MM UK Trading Ltd | Information & communication | 2014 |
| MM3 Ltd | Real estate | 2021 |
| MMB Consulting Services Limited | Professional & scientific | 2024 |
| MMB Retail Limited | Wholesale & retail | 2023 |
| MMC Investco Limited | Other services | 2026 |
| MMI Investments Limited | Real estate | 2011 |
| MMI Land Limited | Real estate | 1986 |
| MMN ENT Ltd | Health & social care | 2022 |
| Mmsc Property Ltd | Real estate | 2025 |
| Mncl Consulting Ltd | Information & communication | 2021 |
| Mnvc UK Ltd | Financial services | 2025 |
| MO Aneese Limited | Professional & scientific | 2024 |
| Moanam Investments Limited | Financial services | 2020 |
| Mobile Identity & Access Management Ltd | Real estate | 2015 |
| Mobile Tech Services Ltd | Professional & scientific | 2018 |
| Mobileum UK Holdings Limited | Financial services | 2018 |
| Mobileum UK Limited | Information & communication | 2007 |
| Mocca Capital Ltd | Financial services | 2023 |
| Modality Property Limited | Real estate | 2009 |
| Model Holdings Ltd | Real estate | 2022 |
| Model Homes Limited | Real estate | 2021 |
| Model Outcomes Ltd | Administrative & support | 2013 |
| Model Property Limited | Real estate | 2018 |
| Modelbridge Consulting Limited | Professional & scientific | 2026 |
| Modern Arts Dental Limited | Health & social care | 2023 |
| Modern Software Solutions Limited | Professional & scientific | 2022 |
| Modernedge Software Limited | Professional & scientific | 2023 |
| Modernmode Limited | Professional & scientific | 2001 |
| Moe's Automotive Services Ltd | Professional & scientific | 2026 |
| Moelia MED Plast Limited | Health & social care | 2025 |
| Mohammad Ali-Abbas Hussain Ltd | Health & social care | 2024 |
| Moldow UK Limited | Manufacturing | 2020 |
| Molecular Glue Labs Ltd | Professional & scientific | 2024 |
| Molloy Hale Investments Limited | Construction | 2019 |
| Molloy Hale Ltd | Construction | 2010 |
| Mollyarth Ltd | Administrative & support | 2025 |
| Moma Properties Ltd | Households | 2022 |
| Momentum Property Services Limited | Construction | 2016 |
| Monahsal Limited | Health & social care | 2023 |
| Monarchs Chase (Fulwood) Management Company Limited | Households | 2013 |
| Monbretia Limited | Administrative & support | 2022 |
| Monet & Co. Ltd | Professional & scientific | 2021 |
| MONET22CONSULTING Ltd | Information & communication | 2026 |
| Moneta Consultancy Holdings Limited | Financial services | 2019 |
| Moneta Consultancy Limited | Other services | 2011 |
| Money Results Limited | Financial services | 2008 |
| Money-Save Service Station Limited | Wholesale & retail | 1981 |
| Monica Davies Business Services Limited | Administrative & support | 2014 |
| Monitoring Limited | Financial services | 1991 |
| Monitoring Technologies Limited | Manufacturing | 1997 |
| Monmouth Court RTM Company Limited | Households | 2025 |
| Monodata Limited | Information & communication | 2025 |
| Monsal Holdings Limited | Professional & scientific | 2007 |
| Monsal Limited | Professional & scientific | 1995 |
| Montgomery Estates LLP | | 2010 |
| Monty Marks Productions Limited | Administrative & support | 2020 |
| MOO Limited | Information & communication | 2004 |
| Moobop Intelligence Ltd | Information & communication | 2013 |
| Mooch Hotels Ltd | Information & communication | 2024 |
| Moodluxe Ltd | Wholesale & retail | 2013 |
| Moon & Back Films Limited | Information & communication | 2015 |
| Moonbeam Lighting Limited | Wholesale & retail | 2016 |
| Moonbeam Press Limited | Information & communication | 2026 |
| Moonchild Tattoo Ltd | Other services | 2018 |
| Moonlight Medicare Limited | Other services | 2022 |
| Moonlight World Limited | Wholesale & retail | 2021 |
| Moonsage Limited | Professional & scientific | 2024 |
| Moore Doeren Mayhew Limited | Professional & scientific | 2017 |
| Moore Financial Services Limited | Professional & scientific | 2013 |
| Moorfield House Management Company Limited | Households | 2002 |
| Moorfields Industrial Estate Limited | Real estate | 2022 |
| Moors Family Investment Company Limited | Financial services | 2021 |
| Mora Interiors Ltd | Wholesale & retail | 2025 |
| Morala Ltd | Manufacturing | 2021 |