| Mind Your P'S & Q'S Ltd | Financial services | 2019 |
| Mindful Rebel Coaching Limited | Wholesale & retail | 2013 |
| Mindful Solutions London Limited | Professional & scientific | 2013 |
| Minerva Consultants Limited | Professional & scientific | 1990 |
| Mingau Limited | Energy | 2021 |
| Mini MOI Ltd | Wholesale & retail | 2018 |
| Minicams North Limited | Information & communication | 2018 |
| Minkey Developments Ltd | Real estate | 2023 |
| Minns & COE Properties Limited | Real estate | 2024 |
| Mino Process Control Limited | Professional & scientific | 2009 |
| Minster Aesthetics Limited | Health & social care | 2022 |
| Minster Bridal Boutique Ltd | Wholesale & retail | 2017 |
| Minster Carpentry Ltd | Construction | 2025 |
| Minster Commercial & General Limited | Professional & scientific | 2015 |
| Minster Construction & Landscaping Limited | Administrative & support | 2025 |
| Minster Decking Limited | Construction | 2022 |
| Minster Gate Management Company Limited | Households | 2001 |
| Minster Investments and Trusts Limited | Financial services | 2018 |
| Minster Maintenance Limited | Administrative & support | 2023 |
| Minster Mechanics Ltd | Wholesale & retail | 2007 |
| Minster Plumbing Ltd | Construction | 2008 |
| Minster Property Management Ltd | Households | 2008 |
| Mintmoice Limited | Hospitality | 2021 |
| Miombo Limited | Information & communication | 2015 |
| Miss Wrapz Ltd | Professional & scientific | 2023 |
| Mission Creative Ltd | Information & communication | 2011 |
| Mission Rabies Limited | Professional & scientific | 2014 |
| Mistral Technology Limited | Information & communication | 2019 |
| Misty Blue Fishing Limited | Agriculture & fishing | 2025 |
| Mitchell Geoconsulting Ltd | Professional & scientific | 2021 |
| Mitos Relocation Solutions Limited | Other services | 2024 |
| Mitosolutions Ltd | Professional & scientific | 2020 |
| Mitre Rail Limited | Administrative & support | 2004 |
| Mixr Ltd | Information & communication | 2011 |
| Mizono Autos Ltd | Wholesale & retail | 2025 |
| MJ Aldridge & Associates Limited | Information & communication | 2020 |
| MJ Mechanical Design Limited | Professional & scientific | 2011 |
| MJ Movers Ltd | Transport & logistics | 2025 |
| MJB Dorset Limited | Financial services | 2021 |
| MJJ Drinks Ltd | Information & communication | 2019 |
| Mjoy Consultancy Limited | Professional & scientific | 2025 |
| MJP Landscapes Limited | Construction | 2019 |
| MJP Law Financial Services Limited | Financial services | 2023 |
| MJP Law Limited | Professional & scientific | 2010 |
| MJP Mortgage & Financial Services Limited | Financial services | 2023 |
| MJS Delivery Dynamics Limited | Information & communication | 2023 |
| MJT Property Investments Limited | Real estate | 2018 |
| MK Gourmet Kitchen Ltd | Hospitality | 2026 |
| MK Validation Limited | Professional & scientific | 2024 |
| Mkeb Bournemouth Ltd | Real estate | 2024 |
| MKJ Car Sales Limited | Wholesale & retail | 2014 |
| ML Technologies Ltd | Information & communication | 2019 |
| MLG Solutions Limited | Information & communication | 2020 |
| MM Data Engineering Solutions Ltd. | Information & communication | 2016 |
| MM Ingredients Limited | Manufacturing | 2007 |
| MM Satori Consulting Limited | Information & communication | 2022 |
| Moatstar Limited | Real estate | 1973 |
| Mobile Bouldering Company Ltd | Arts & recreation | 2014 |
| Mobile Unmasked Limited | Information & communication | 2024 |
| Mobility Station Ltd | Extraterritorial | 2020 |
| Mobinato Consulting Limited | Professional & scientific | 2018 |
| Moderation Projects Limited | Professional & scientific | 2024 |
| Moeder Ltd | Professional & scientific | 2025 |
| Mokkai Limited | Real estate | 2025 |
| Moku Digital Ltd | Information & communication | 2014 |
| Mole & Sons Roofing Services Limited | Construction | 2026 |
| Momentumbpo Limited | Professional & scientific | 2020 |
| Monaco Entertainment Agency Ltd | Other services | 2024 |
| Monad Technologies Ltd | Information & communication | 2019 |
| Monique Care Ltd | Health & social care | 2015 |
| Mono Delgado Limited | Other services | 2008 |
| Monogram Media Ltd | Information & communication | 2015 |
| Monos Roofing Ltd | Construction | 2025 |
| Montrose Smallholding Developments Ltd | Agriculture & fishing | 2024 |
| Moonacre Dorset Limited | Hospitality | 2026 |
| Moonfleet Marketing Ltd | Professional & scientific | 2025 |
| Moonlight by Megan Ltd | Wholesale & retail | 2022 |
| Moorhills Flats Limited | Households | 1974 |
| Moors Valley Motorcycles Limited | Wholesale & retail | 1993 |
| Moortown Dairy Management Limited | Households | 2001 |
| Moose & EMU Productions Limited | Information & communication | 2012 |
| Mordernstack Limited | Information & communication | 2025 |
| Mordialloc Transport Services Ltd | Transport & logistics | 2024 |
| Morefertile Ltd | Extraterritorial | 2014 |
| Morethanav Limited | Wholesale & retail | 2025 |
| Morning View Properties Limited | Hospitality | 2022 |
| Morris Construction Limited | Construction | 2011 |
| Morrisfever Ltd | Administrative & support | 2021 |
| Morton Findlay Associates Limited | Professional & scientific | 2016 |
| Motion Drywall Ltd | Construction | 2019 |
| Motsi Engineering Ltd | Wholesale & retail | 2025 |
| Moulding Optimisation Ltd | Professional & scientific | 2015 |
| Movement House Ltd | Arts & recreation | 2026 |
| Movingplaces.Co.Uk Limited | Real estate | 1999 |
| Moxy Construction Ltd | Construction | 2023 |
| MP & DA Ltd | Administrative & support | 2020 |
| MP Calibration Services Limited | Professional & scientific | 2003 |
| Mploy (Dorset) Limited | Administrative & support | 2009 |
| MPN Property Services Limited | Real estate | 2019 |
| MPW (Service) LLP | | 2022 |