| M B Stone Installations Ltd | Construction | 2004 |
| M D Wood & Sons Carpentry & Building Limited | Construction | 2021 |
| M F Scaffolding Ltd | Construction | 2014 |
| M J Hardman & Grandsons Electrical Limited | Construction | 2017 |
| M K C Properties Limited | Administrative & support | 2006 |
| M L M B Property Ltd | Real estate | 2025 |
| M Rowe Ltd | Real estate | 2016 |
| M S Pipe Services Limited | Construction | 2012 |
| M Squared Commercial Cleaning Ltd | Administrative & support | 2025 |
| M Tech & Repair Limited | Manufacturing | 2026 |
| M Turner Grab Hire Ltd | Transport & logistics | 2025 |
| M Wright Ltd | Wholesale & retail | 2020 |
| M&A Dream Toys Ltd | Wholesale & retail | 2022 |
| M&A Property Services Ltd | Real estate | 2020 |
| M&B Interiors Ltd | Construction | 2018 |
| M&M Enterprise Group Ltd | Hospitality | 2024 |
| M&M Holdings (Kent) Ltd | Real estate | 2025 |
| M&M Kent Ltd | Real estate | 2022 |
| M.A. Chimason Ltd | Construction | 2020 |
| M.A.O South East Ltd | Construction | 2018 |
| M.Kanin Limited | Hospitality | 2024 |
| M.M.A Highway Services Limited | Wholesale & retail | 2019 |
| M.R Building Limited | Construction | 2026 |
| M.S.P. Holdings | Real estate | 1962 |
| M25 Drainage Limited | Construction | 2019 |
| M4 Invest Ltd | Real estate | 2021 |
| MA Freight Ltd | Transport & logistics | 2025 |
| MA Software Ltd | Information & communication | 2018 |
| Maam Ltd | Hospitality | 2026 |
| Mable Property Services Ltd | Real estate | 2024 |
| Maboat's Kravns Ltd | Hospitality | 2024 |
| MAC Bedrooms and Kitchens Limited | Construction | 2020 |
| MAC Business Solutions Ltd | Professional & scientific | 2013 |
| MAC Fhearadhaigh Ltd | Construction | 2018 |
| Maceo Properties Limited | Real estate | 2024 |
| Maci Parry Ltd | Professional & scientific | 2024 |
| Mackario Company Ltd | Transport & logistics | 2021 |
| Maclean Capital Limited | Real estate | 2025 |
| Macro Pest Control Limited | Administrative & support | 2019 |
| Madas Healthcare Services Ltd | Health & social care | 2011 |
| Made 2 Maid Ltd | Administrative & support | 2015 |
| Made by Mensa Ltd | Manufacturing | 2018 |
| Made by Mindy Ltd. | Arts & recreation | 2022 |
| Made in Italy (Gravesend) Ltd | Hospitality | 2024 |
| Madebyjaydee UK Ltd | Wholesale & retail | 2025 |
| Madpad Properties Ltd | Real estate | 2025 |
| Madron Ltd | Transport & logistics | 2021 |
| MAE Sommers Ltd | Real estate | 2016 |
| Maeynu Limited | Health & social care | 2024 |
| Magic Duster Cleaning Ltd | Administrative & support | 2025 |
| Magic Duster Limited | Administrative & support | 2012 |
| Magic Scissors (TW) Limited | Other services | 2023 |
| Magic Scissors Southborough Limited | Other services | 2024 |
| Magsam Services Ltd | Transport & logistics | 2019 |
| Mahil Logistics Limited | Transport & logistics | 2021 |
| Maid in Vigo Ltd | Administrative & support | 2025 |
| Maids to Order Ltd | Administrative & support | 2018 |
| Maidstone Electrolysis & Laser Clinic Ltd | Other services | 2025 |
| Maidtotheperfectionuk Ltd | Administrative & support | 2021 |
| Main Road 241 Management Ltd | Households | 2023 |
| Mainline Projects Ltd | Information & communication | 2026 |
| Maison Maurice Limited | Wholesale & retail | 1977 |
| Majestic Contract Services Limited | Construction | 2014 |
| Majestic Gyms Limited | Other services | 2008 |
| Majestic Orbits Children’S Home Limited | Health & social care | 2026 |
| Majoris Solutions Limited | Professional & scientific | 2015 |
| MAK Social Solutions Limited | Health & social care | 2023 |
| Making Magic Ltd | Education | 2019 |
| Makins-Link Limited | Transport & logistics | 2020 |
| Malayuk Limited | Construction | 2015 |
| Malcolm Horton and Co Ltd | Professional & scientific | 2005 |
| Malentity Ltd | Professional & scientific | 2019 |
| Malex Logistic Ltd | Transport & logistics | 2015 |
| Malhi Brothers Construction Ltd | Construction | 2019 |
| Malik Consultancy Inc Limited | Financial services | 2017 |
| Malik Healthcare Management Limited | Real estate | 2013 |
| Malling Repair Services Kent Ltd | Professional & scientific | 2019 |
| Malnat Protection Services Limited | Administrative & support | 2018 |
| Malt Building Services Limited | Construction | 2006 |
| Malwa Construction Work Ltd | Construction | 2020 |
| Malway Logistics Ltd | Transport & logistics | 2022 |
| MAM Agus Daid Properties Ltd | Real estate | 2026 |
| Mama G Jollof Ltd | Hospitality | 2018 |
| Mama Garri Ltd | Hospitality | 2021 |
| Mamadi Intl Ltd | Wholesale & retail | 2025 |
| Mamre Insight Ltd | Professional & scientific | 2021 |
| Managed Magnanimous Portfolio Services UK Ltd | Information & communication | 2014 |
| Manetta Holdings Limited | Real estate | 2022 |
| Mango Cleaning Ltd | Other services | 2014 |
| Manik Munch Limited | Hospitality | 2019 |
| Mann Fitness Group Ltd | Arts & recreation | 2023 |
| Mann Trucking Ltd | Transport & logistics | 2024 |
| Manny Productions Ltd | Information & communication | 2024 |
| Manor Cottage Properties Limited | Real estate | 2018 |
| Manor Daycare Limited | Education | 2015 |
| Manor Farm Estate Farningham (Management) Limited | Households | 1984 |
| Manraj Lidder Limited | Professional & scientific | 2019 |
| Mansion Estates & Management Limited | Real estate | 2020 |
| Mansion Mortgages Limited | Financial services | 2018 |
| Mansk Group Ltd | Real estate | 2022 |