| Maintain My House Ltd | Construction | 2026 |
| Making Change Work Ltd | Professional & scientific | 2007 |
| Manderley House Management Company Limited | Real estate | 2010 |
| Manor View Management Company Limited | Households | 2002 |
| Mapyx Limited | Information & communication | 2006 |
| Mariposa Creations Ltd | Wholesale & retail | 2018 |
| Maritime House Management Co Ltd | Real estate | 2003 |
| Marmaris Kurdish Barber Ltd | Other services | 2022 |
| Marshalls Jewellery Ltd | Manufacturing | 2025 |
| Mash Media Cafe Ltd | Professional & scientific | 2016 |
| Maudlins Lane (1-6) Limited | Households | 2009 |
| Maytham Vascular Limited | Health & social care | 2014 |
| Mazuwa Energy Ltd | Energy | 2025 |
| Mazuwa Estates Ltd | Energy | 2025 |
| Mazuwa Ltd | Energy | 2025 |
| Mazuwa Wealth Ltd | Financial services | 2025 |
| MBC Accountants Ltd | Extraterritorial | 2018 |
| Mcdiarmid Holdings Limited | Professional & scientific | 2008 |
| Mcdiarmid Spa Limited | Professional & scientific | 2008 |
| Meldon Lodge Park Ltd | Hospitality | 2015 |
| MID Surrey Renovators Limited | Construction | 2008 |
| Mike Bates and Sons Ltd | Construction | 2026 |
| Millie's Attic Limited | Wholesale & retail | 2010 |
| MJ Smith Earthmoving and Construction Limited | Professional & scientific | 2006 |
| MJE Management Consultancy Ltd | Professional & scientific | 2014 |
| MK Dentist Ltd | Health & social care | 2025 |
| MM Coaching Ltd | Health & social care | 2026 |
| MMS Mobile Mechanic Ltd | Wholesale & retail | 2023 |
| Modern Diners Limited | Hospitality | 2012 |
| Modular Cubed Ltd | Construction | 2016 |
| Monks Construction Limited | Construction | 2010 |
| Moor Economics Limited | Professional & scientific | 2019 |
| Moor Independent Financial Advisers Limited | Financial services | 2022 |
| Moor Lane Market Garden CIC | Agriculture & fishing | 2026 |
| Moor TAW Limited | Agriculture & fishing | 2023 |
| Moor Training Limited | Professional & scientific | 2016 |
| Moorshop Limited | Information & communication | 2018 |
| Moovafy Ltd | Information & communication | 2023 |
| Mops & Buckets Southwest Ltd | Administrative & support | 2019 |
| MOT My House Ltd | Professional & scientific | 2024 |
| Motor & Country South West Ltd | Other services | 2022 |
| Motorhome Marketplace (Norfolk & Peterborough) Ltd | Wholesale & retail | 2022 |
| Mount Moore Consulting Limited | Professional & scientific | 2014 |
| MPS Transport & Sons Ltd | Transport & logistics | 2019 |
| Mrlk Limited | Professional & scientific | 2019 |
| MS Carpentry (SW) Ltd | Construction | 2026 |
| MSL Machine Movers Ltd | Construction | 2015 |
| Mucky Duck Management Company Limited | Households | 2003 |
| Museum of Policing in Devon & Cornwall | Arts & recreation | 2016 |
| MV Rural Services Ltd | Agriculture & fishing | 2024 |
| MW Chemical Services Limited | Professional & scientific | 2010 |
| MW Homes & Investments Limited | Real estate | 2025 |
| My Business Centre Limited | Professional & scientific | 2004 |
| My Perfect Pitch Ltd | Hospitality | 2025 |
| My Performance Coach Limited | Professional & scientific | 2023 |
| My Way Support CIC | Hospitality | 2020 |
| N V Motors Limited | Wholesale & retail | 2002 |
| Naked House Community Builders C.I.C. | Construction | 2013 |
| NDM Distribution Ltd | Wholesale & retail | 2014 |
| Netilio Ltd | Information & communication | 2016 |
| New Distribution Ltd | Wholesale & retail | 2024 |
| New Media Horizons Ltd | Information & communication | 2000 |
| Newdav Ltd | Real estate | 2021 |
| Nibbles Cafe Ltd | Hospitality | 2023 |
| Nick Camp Consulting Ltd | Professional & scientific | 2018 |
| Nick Lands Ltd | Arts & recreation | 2023 |
| Nick Mackman Animal Sculpture Ltd | Arts & recreation | 2021 |
| Nilssons IS Ltd | Professional & scientific | 2022 |
| NJB Automotive Services Ltd | Wholesale & retail | 2018 |
| NO.1 Coffee Ltd | Wholesale & retail | 2020 |
| NO.1 Foods Ltd | Hospitality | 2021 |
| NO.1 Pizza Bros Ltd | Hospitality | 2026 |
| NO.10 Ltd | Other services | 2017 |
| Nomad Design Limited | Arts & recreation | 2002 |
| Nomad Rider Ltd | Wholesale & retail | 2022 |
| North & Nest Ltd | Administrative & support | 2025 |
| North Wonson Farm Limited | Agriculture & fishing | 1993 |
| Northmoor Associates Ltd | Information & communication | 2019 |
| Northmoor Properties Ltd | Hospitality | 2021 |
| Northmore Arms Limited | Hospitality | 2010 |
| O'Connors Hire Limited | Arts & recreation | 2011 |
| Oafc Social Club Ltd | Hospitality | 2021 |
| Oak Residential Developments Limited | Administrative & support | 2018 |
| Oak Valley Tree Services Ltd | Agriculture & fishing | 2021 |
| Oaken Auditing Services Ltd | Administrative & support | 2025 |
| Oaklands Park Limited | Administrative & support | 1984 |
| Oaks Montessori Ltd | Administrative & support | 2020 |
| OBI Engineering Ltd | Water & waste | 2015 |
| Ocas Services Ltd | Education | 2018 |
| Ocean View Studios Ltd | Information & communication | 2019 |
| Oceanview Technical Ltd | Transport & logistics | 2025 |
| Ockington View Apartments Management Company Limited | Real estate | 2015 |
| Ockington View Management Company Limited | Real estate | 2014 |
| Ockment Centre | Administrative & support | 2006 |
| Odstone Farms Limited | Agriculture & fishing | 1959 |
| OKE Barber Ltd | Other services | 2024 |
| OKE Grill Limited | Hospitality | 2025 |
| OKE Spice Ltd | Hospitality | 2023 |
| OKE Tree Network LLP | | 2022 |
| Oked Ltd | Education | 2023 |