| Moreland Nuclear Limited | Professional & scientific | 2020 |
| Morganised Ltd | Professional & scientific | 2023 |
| Morgann Limited | Health & social care | 2019 |
| Motor Trade Signs Limited | Manufacturing | 2003 |
| Movement Snax Ltd | Other services | 2025 |
| Movere Limited | Information & communication | 2024 |
| Mpav Limited | Information & communication | 2019 |
| MPS Glass Ltd | Construction | 2022 |
| MPT Fitness Limited | Arts & recreation | 2021 |
| MR Auto Rentals Ltd | Administrative & support | 2026 |
| MR Socket Limited | Construction | 2024 |
| MR UK Bulls Limited | Agriculture & fishing | 2019 |
| MR. Milestone Limited | Professional & scientific | 2024 |
| MS Autocare (Leighton Buzzard) Limited | Wholesale & retail | 2024 |
| MSA Raising Ltd | Financial services | 2024 |
| MSC Planning Associates Limited | Professional & scientific | 2019 |
| MSC Planning Holdings Limited | Financial services | 2023 |
| MSP Spares Ltd | Wholesale & retail | 2021 |
| MT Fabricators Ltd | Manufacturing | 2018 |
| MT Land Ltd | Real estate | 2020 |
| MT Nacorda Aviation Limited | Manufacturing | 2015 |
| Mtape Ltd | Health & social care | 2023 |
| Muhib Healthcare Ltd | Health & social care | 2024 |
| Mula Blockchain (UK) Ltd | Financial services | 2021 |
| Mulberry Diagnostics Ltd | Health & social care | 2026 |
| Mumbles Coach and Minibuses Ltd | Extraterritorial | 2013 |
| Mums and Little Bums Limited | Professional & scientific | 2010 |
| Musama Connection Ltd | Administrative & support | 2016 |
| Musashi Golf Travel Ltd | Wholesale & retail | 2026 |
| Musial Accounting Services Ltd | Professional & scientific | 2021 |
| Musical Theatre High! Ltd | Arts & recreation | 2011 |
| MVC Technology Limited | Information & communication | 2025 |
| MVP Property Partners Ltd | Real estate | 2025 |
| MW Consultancy Services Ltd | Information & communication | 2009 |
| MW Design & Consulting Limited | Professional & scientific | 2007 |
| My Club Merch Limited | Wholesale & retail | 2025 |
| My Home Workspace Ltd | Construction | 2020 |
| My Law Legal Ltd | Professional & scientific | 2024 |
| My Positive Future Ltd | Health & social care | 2023 |
| Mymailshot.Com Limited | Information & communication | 2011 |
| Myvirtualbookkeeper.Co.Uk Limited | Professional & scientific | 2017 |
| Mzmk Group Ltd. | Real estate | 2024 |
| N & L Builders Ltd | Construction | 2017 |
| N K Auto Group Ltd | Wholesale & retail | 2025 |
| N M Bunker Limited | Construction | 2007 |
| N Roberts Limited | Professional & scientific | 2021 |
| Narvalo Limited | Information & communication | 2024 |
| Natalie Amabel Sanders Ltd | Extraterritorial | 2025 |
| Nathan James Music Limited | Information & communication | 2014 |
| Naycott Estates Limited | Real estate | 2017 |
| NBL Trading Ltd | Other services | 2018 |
| Nbmdd Ltd | Hospitality | 2025 |
| NDC Utility Services Ltd | Energy | 2015 |
| NE Energy One Limited | Energy | 2012 |
| Neate Marketing Limited | Professional & scientific | 2016 |
| Nedtrans Ltd | Transport & logistics | 2015 |
| Neha and Shubham Ltd | Real estate | 2023 |
| Neil a Dawson & Company Limited | Administrative & support | 2019 |
| Neil Crow Consulting Limited | Professional & scientific | 2017 |
| Neil Douglas Block Management Limited | Real estate | 2010 |
| Nelson Sisters Ltd | Hospitality | 2016 |
| Nerdworking Ltd | Administrative & support | 2024 |
| Nest Investment Holdings Ltd | Real estate | 2026 |
| Nestor Services Ltd | Professional & scientific | 2015 |
| Netlink Telecoms Ltd | Construction | 2025 |
| Netquantum Limited | Information & communication | 2018 |
| Neurocyber CIC | Information & communication | 2021 |
| Neurodiversity MK Solutions Ltd | Professional & scientific | 2021 |
| Neurohex Systems Ltd | Information & communication | 2025 |
| Neva Business Finance Ltd | Financial services | 2026 |
| Never Enough Songs Ltd | Information & communication | 2024 |
| New Bureau Limited | Professional & scientific | 2022 |
| New Bury Park Events Limited | Hospitality | 2009 |
| New ERA Heating, Plumbing & Household Maintenance Ltd | Administrative & support | 2016 |
| New Fone UK Limited | Wholesale & retail | 2022 |
| New Horizon Transport Ltd | Construction | 2025 |
| New Leisure (MK) Limited | Professional & scientific | 2003 |
| New Ocean Fish Bar I Ltd | Hospitality | 2018 |
| Newington Retail Services | | 1998 |
| Newsom Place Management Company Limited | Households | 2007 |
| Newton Keane Contractors Ltd | Construction | 2009 |
| Newtown Sideloaders Southern Limited | Wholesale & retail | 1984 |
| Nexapayroll Ltd | Professional & scientific | 2026 |
| Next Intelligence Limited | Financial services | 1996 |
| Nexus Domus Limited | Households | 2018 |
| Nexus Insight Limited | Wholesale & retail | 2009 |
| Nexus Migration Ltd | Administrative & support | 2025 |
| Nexusfitnessandwellbeing Limited | Arts & recreation | 2026 |
| Nfix UK Limited | Information & communication | 2013 |
| NFM Scenery Ltd | Information & communication | 2025 |
| Ngolee Productions Limited | Wholesale & retail | 2022 |
| Niche VA Services Limited | Professional & scientific | 2025 |
| Nichetek Solutions Limited | Information & communication | 2023 |
| Nicholas Finburgh Ltd | Manufacturing | 2008 |
| Nick Edits Ltd | Information & communication | 2018 |
| Nick-Nack Physio Ltd | Public administration | 2023 |
| Nickmcellarservices Limited | Construction | 2025 |
| Nigel Harding Associates Limited | Hospitality | 1997 |
| Nightingale Rise Buckingham Management Company Limited | Real estate | 2016 |
| Nine Zillion and Three Limited | Professional & scientific | 2023 |