| Monticook Catering Ltd | Wholesale & retail | 2019 |
| Montreal Mews Ltd | Real estate | 2017 |
| Monty Piper (Carpets & Flooring) Ltd | Construction | 2007 |
| Monty Touring Limited | Arts & recreation | 2025 |
| Moodliar's Developers Ltd | Real estate | 2024 |
| Mooláe Limited | Real estate | 2026 |
| Moor Lodge Bloodstock Limited | Agriculture & fishing | 2024 |
| More Comms (East Anglia) Ltd | Construction | 2013 |
| More Creativity Limited | Extraterritorial | 2008 |
| More Light Limited | Professional & scientific | 2014 |
| Moreefficient Consulting Ltd | Information & communication | 2024 |
| Morris Medical Limited | Health & social care | 2019 |
| Mortgage-Geeksuk Ltd | Financial services | 2026 |
| Mortham Street Management Company Limited | Real estate | 2006 |
| Moss Carpentry Ltd | Construction | 2018 |
| Mossec Services Ltd | Manufacturing | 2010 |
| Most Wanted Group Limited | Wholesale & retail | 2020 |
| Motherloded Limited | Information & communication | 2014 |
| Mountcharge Limited | Wholesale & retail | 2002 |
| Move and Clean Ltd | Administrative & support | 2025 |
| Moving Cameras Limited | Information & communication | 2016 |
| Mozi Trendz Ltd | Manufacturing | 2019 |
| MP Traffic Solutions Ltd | Construction | 2018 |
| MPD Driver Hire Ltd | Transport & logistics | 2023 |
| Mpowder Ltd | Wholesale & retail | 2019 |
| MR Aras Limited | Administrative & support | 2024 |
| MR B'S Proper Walks Ltd | Health & social care | 2019 |
| MR ELY Recovery Ltd | Wholesale & retail | 2023 |
| MR Squeaky Clean Ltd | Administrative & support | 2011 |
| MRB Brickwork Ltd | Construction | 2018 |
| MRH Contracting Ltd | Construction | 2026 |
| MSC Naturally Limited | Wholesale & retail | 2018 |
| MSH Investors Limited | Real estate | 2023 |
| MSN Retail Limited | Wholesale & retail | 2023 |
| MSS Carpentry Limited | Manufacturing | 2023 |
| MTJ King Ltd | Real estate | 2026 |
| Mufty Ltd | Information & communication | 2024 |
| Mulberry Close Limited | Administrative & support | 2023 |
| Mumtaztic Ltd | Extraterritorial | 2025 |
| Munro Consultants Limited | Professional & scientific | 2010 |
| Munro RTM Limited | Households | 2018 |
| Munt Property Holdings Ltd | Real estate | 2017 |
| Murfet (Cutlers Forge) Ltd | Construction | 2020 |
| Murfet Oyster ROW Limited | Construction | 2018 |
| Murfitt Holdings Limited | Extraterritorial | 2019 |
| Mushroom Farms Holdings Limited | Financial services | 2022 |
| Mushrooms Holdings Ltd | Financial services | 2022 |
| Musora Plumbing Limited | Construction | 2025 |
| Mwata Limited | Wholesale & retail | 2024 |
| MWS Architectural Ltd | Professional & scientific | 2013 |
| Myatts View Management Limited | Households | 2002 |
| Mychap Ltd | Information & communication | 2017 |
| Myriad Self-Storage (Grimsby) Limited | Other services | 2022 |
| Myriad Self-Storage Limited | Real estate | 2017 |
| N & C Glazing and Frames Limited | Professional & scientific | 1994 |
| N & D Property Development Limited | Construction | 2001 |
| N M Edwards Transport Ltd | Transport & logistics | 2024 |
| N R Plumbing & Heating Limited | Construction | 2009 |
| N-Chem Consultancy Ltd | Health & social care | 2023 |
| N-Mac Consulting Ltd | Professional & scientific | 2013 |
| N. & M. Sizer Limited | Agriculture & fishing | 1983 |
| N. R. Harris Limited | Financial services | 2009 |
| N.G. Uttridge Limited | Construction | 2006 |
| Nailpro Infinity Ltd | Other services | 2023 |
| Narbutas Dental Limited | Health & social care | 2023 |
| Nash & Skeels Limited | Construction | 2024 |
| Natalie Marie Aesthetics Ltd | Health & social care | 2025 |
| Natural Scenics Limited | Other services | 2007 |
| Navigate Planning Limited | Professional & scientific | 2020 |
| NAZ High Street Limited | Hospitality | 2024 |
| Neals Travel Limited | Transport & logistics | 1993 |
| Neatconsult Ltd | Professional & scientific | 2021 |
| Needles & Thread Ltd | Wholesale & retail | 2025 |
| Nemesys Computer Consultants Limited | Information & communication | 1994 |
| Neofab-Uk Ltd | Professional & scientific | 2021 |
| NEST47 Ltd | Real estate | 2025 |
| Never Back Down - Mental Health Awareness Ltd | Wholesale & retail | 2025 |
| New Carpentry Limited | Construction | 2007 |
| New Fit Ltd | Arts & recreation | 2023 |
| New Marque Motorhomes Ltd | Wholesale & retail | 2018 |
| Newmarket Prestige Travel Limited | Transport & logistics | 2025 |
| Newnham Street Carpets Limited | Wholesale & retail | 2017 |
| Newport (2024) Ltd | Real estate | 2024 |
| Newton Watters Property Ltd | Real estate | 2022 |
| Newton-In-The-Isle Vineyard Limited | Agriculture & fishing | 2024 |
| Next Chapter Developments Limited | Real estate | 2025 |
| Nextgen Digital Marketing Ltd | Professional & scientific | 2025 |
| Nexus IE Limited | Manufacturing | 2012 |
| NG & Sons Trading Ltd | Wholesale & retail | 2026 |
| Ngcliff Services Ltd | Other services | 2018 |
| Nick Leonard Building Services Ltd | Professional & scientific | 2018 |
| Night Drive Records Ltd | Wholesale & retail | 2026 |
| Nikniks (ELY) Limited | Other services | 2017 |
| Nishantha Ltd | Administrative & support | 2026 |
| Nivlam LLP | | 2013 |
| Nlpt Fitness Ltd | Other services | 2023 |
| NM FFF Coaching LLP | | 2025 |
| NMA Ventures Limited | Manufacturing | 2011 |
| Noesis Intelligence Ltd | Information & communication | 2026 |
| Nohree Ltd | Wholesale & retail | 2025 |