| Mark Moore-Gillon Executive Coaching and Consulting Limited | Administrative & support | 2017 |
| Market House Investments Limited | Real estate | 1999 |
| Market House Limited | Construction | 1992 |
| Markey Alexander Ltd | Professional & scientific | 2023 |
| Marlborough House School Trust Limited | Education | 1957 |
| Marshall Heating Ltd | Construction | 2007 |
| Martial Arts Boxing Academy Ltd | Arts & recreation | 2020 |
| Martins of Hawkhurst Limited | Wholesale & retail | 2015 |
| Mary Ensor Limited | Real estate | 1987 |
| Maryview Commercial Limited | Professional & scientific | 2022 |
| Matchwise Ltd | Information & communication | 2026 |
| Mathtech Consultants Limited | Professional & scientific | 2011 |
| Matrix Claims Services Limited | Professional & scientific | 2005 |
| Matrix Insurance Services Limited | Financial services | 2005 |
| Matrix+ Consulting UK Limited | Mining & quarrying | 2005 |
| Maua Kenyan Flower Collective Limited | Wholesale & retail | 2025 |
| Maxrol Limited | Professional & scientific | 2013 |
| Maypole First Consulting Limited | Administrative & support | 2013 |
| MB Hygiene & Therapy Ltd | Health & social care | 2013 |
| Mcgeachy Garden Design Limited | Administrative & support | 2016 |
| MDS Shows Ltd | Administrative & support | 2013 |
| MEG Evans Ltd | Information & communication | 2017 |
| MEL Nason Limited | Wholesale & retail | 2015 |
| Memory of China Ltd | Hospitality | 2020 |
| Meridian DRY Lining Limited | Construction | 2004 |
| Merin Business Systems Ltd | Real estate | 1994 |
| Mermaid Leisure Distribution Ltd | Wholesale & retail | 2022 |
| Mermaid Leisure Products Ltd | Wholesale & retail | 2022 |
| Meta Capability Limited | Other services | 2018 |
| Meta Team Limited | Professional & scientific | 2020 |
| Metric Flooring LLP | | 2009 |
| Mhav Tech Ltd | Manufacturing | 2024 |
| Middleton Land Ltd | Real estate | 2017 |
| Mikes Home and Garden Ltd | Wholesale & retail | 2019 |
| Miketech ADS Limited | Administrative & support | 2020 |
| Military Grave Restorer CIC | Administrative & support | 2023 |
| Millers Meadow Sandhurst Management Limited | Households | 2022 |
| Milton Project Management Limited | Administrative & support | 2017 |
| MIMI2004 Limited | Financial services | 2014 |
| Mimr Studio Ltd | Information & communication | 2026 |
| Minerva Empowerment Consulting Ltd | Professional & scientific | 2024 |
| Misled Lighting LLP | | 2021 |
| MJS Chantry Ltd | Administrative & support | 2024 |
| Mjwd Fitness Limited | Arts & recreation | 2020 |
| Moen & Co Accountants Limited | Professional & scientific | 2003 |
| Momenta Marketing Limited | Professional & scientific | 2011 |
| Mona Trade Services Ltd | Hospitality | 2023 |
| Moneta Media Ltd | Information & communication | 2007 |
| Montriste Limited | Professional & scientific | 2014 |
| Moonpool Properties Limited | Real estate | 2001 |
| Moorpark Services Limited | Professional & scientific | 2003 |
| Morgan Makes Ltd | Manufacturing | 2023 |
| Morris DB Ltd | Wholesale & retail | 2025 |
| Morrison Govan LLP | | 2016 |
| Mountshill Woodcraft Ltd | Manufacturing | 2020 |
| MR Cleansweep Limited | Administrative & support | 2002 |
| MR Noah’S Nursery School CIC | Education | 2020 |
| MRS T Potts Limited | Wholesale & retail | 2021 |
| Muddle Technologies Limited | Information & communication | 2015 |
| Muddy Pups Parlour Ltd | Other services | 2025 |
| Mulberry House Services Group Ltd | Information & communication | 2022 |
| My Inside Guide Limited | Wholesale & retail | 2018 |
| My Skin Studio Ltd | Other services | 2010 |
| Myrmidon Properties Limited | Real estate | 2025 |
| Nailbird Ltd | Other services | 2023 |
| Nameste Ltd (Trading AS Lighthouse Projects) Ltd | Real estate | 2020 |
| NAS AC Limited | Construction | 2026 |
| Nationwide Roofs Ltd | Construction | 2025 |
| NBF (High Halden) Management Ltd | Real estate | 2024 |
| Nea-Polish Pizza Ltd | Hospitality | 2024 |
| Negishi Sushi Ltd | Hospitality | 2026 |
| Nepeta England Limited | Wholesale & retail | 2024 |
| Neuro Biotech Limited | Professional & scientific | 2020 |
| New Barn Farm Developments Ltd | Other services | 2021 |
| Newenden Meadow Limited | Arts & recreation | 2024 |
| Newenden Quality Kebab Ltd | Hospitality | 2026 |
| Nine Charles Road Freehold Company Limited | Real estate | 2025 |
| NLM Property Group Ltd | Construction | 2026 |
| NO1FITOUT Ltd | Construction | 2023 |
| Nori Management and Consulting Services Limited | Professional & scientific | 2016 |
| North Thorn Ltd | Hospitality | 2021 |
| NP Seymour Limited | Manufacturing | 2008 |
| NU ID Ltd | Information & communication | 2014 |
| Nubio Financial Ltd | Financial services | 2021 |
| O & M IT Limited | Information & communication | 2005 |
| Oakhurst Farms Limited | Real estate | 2000 |
| Oakmere Rentals Ltd | Real estate | 2025 |
| Oaks Consulting Ltd | Information & communication | 2018 |
| Oakstone Property Limited | Real estate | 2007 |
| Oakwater Farm Ltd | Agriculture & fishing | 2022 |
| Oatlee Digital Ltd | Professional & scientific | 2022 |
| OB Plastering Limited | Construction | 2019 |
| Objective Designers Limited | Professional & scientific | 2008 |
| Obtineo Limited | Professional & scientific | 2005 |
| Ockley Barn Farm Limited | Education | 2023 |
| Octane CDE Limited | Information & communication | 2026 |
| Octonaught Ltd | Professional & scientific | 2024 |
| Odyl Design Limited | Wholesale & retail | 2008 |
| Oishii (Cranbrook) Limited | Hospitality | 2022 |
| Old Highgate Holdings Ltd | Real estate | 2021 |