| Moorbrook Residents Management Company Limited | Households | 2018 |
| Moore Building Developments Ltd | Construction | 2023 |
| Moore Carpentry Ltd | Construction | 2026 |
| Moore Close Management Limited | Households | 2022 |
| Moore Connected Ltd | Extraterritorial | 2018 |
| Moore EDS Consultants Ltd | Administrative & support | 2014 |
| Moore Elearning Limited | Education | 2003 |
| Moore Enterprising Limited | Education | 2008 |
| Moore Machine Tools Ltd | Professional & scientific | 2012 |
| Moore Perspectives Limited | Professional & scientific | 2025 |
| Mooreturfcare UK Ltd | Administrative & support | 2024 |
| Moorevape Limited | Wholesale & retail | 2014 |
| Moorhouse Accounting & Consultancy Services Limited | Professional & scientific | 2013 |
| Moorside Business Services LLP | | 2006 |
| Moorspeed Ltd. | Wholesale & retail | 2002 |
| Mootral Limited | Professional & scientific | 2021 |
| Mooveit Ltd | Wholesale & retail | 2024 |
| Moprojects Limited | Construction | 2009 |
| MOR SU Limited | Hospitality | 2015 |
| Morari Robert Ltd | Construction | 2016 |
| Moraru Engineering UK Ltd | Professional & scientific | 2018 |
| Morava Cleaning Services Ltd | Administrative & support | 2026 |
| More Demand Limited | Professional & scientific | 2022 |
| More Driver Solutions Limited | Administrative & support | 2005 |
| More Enterprises Ltd | Administrative & support | 2017 |
| More Industrial Solutions Ltd | Administrative & support | 2024 |
| More Recruitment Group Limited | Professional & scientific | 2022 |
| More Recruitment SLC South Ltd | Administrative & support | 2021 |
| More Recruitment Solutions Limited | Administrative & support | 2016 |
| More Than Just Kpis Ltd | Information & communication | 2024 |
| Morecroft Building Services Limited | Construction | 2015 |
| Morel Properties Limited | Real estate | 2016 |
| Morendi Construction Ltd | Construction | 2022 |
| Moreofthesame Ltd | Professional & scientific | 2023 |
| Moreton Associates Limited | Other services | 2017 |
| Moretonian Investment Limited | Real estate | 2023 |
| Morfin Ltd | Construction | 2017 |
| Morgan and Nephew Health Care Limited | Public administration | 2021 |
| Morgan Care International Ltd | Health & social care | 2020 |
| Morgan Land and Properties Limited | Real estate | 2023 |
| Moriarty FS Support Ltd | Professional & scientific | 2023 |
| Morin UK Limited | Financial services | 2019 |
| Morinville Chipman Ltd | Wholesale & retail | 2026 |
| Morning Star Insights Ltd | Professional & scientific | 2026 |
| Morningside Healthcare Limited | Manufacturing | 2001 |
| Morningside Pharmaceuticals Limited | Manufacturing | 1991 |
| Mornington Sanford Aviation (Training) Limited | Transport & logistics | 2007 |
| Mornmist Properties Limited | Real estate | 2019 |
| Morocco Taverns Ltd | Hospitality | 2024 |
| Morphy & Sons Ltd | Administrative & support | 2017 |
| Morrheat Ltd | Construction | 2015 |
| Morriblaze Ltd | Wholesale & retail | 2025 |
| Morris - Cook Developments Limited | Construction | 2003 |
| Morris Bros.(Great Houghton)Limited | Wholesale & retail | 1962 |
| Morris Clarke Recruitment Ltd | Administrative & support | 2011 |
| Morris Developments Ltd | Construction | 2010 |
| Morris Pascoe Ltd | Construction | 2023 |
| Morris Tech Commercials Ltd | Wholesale & retail | 2026 |
| Morris, Morris & Morris Limited | Real estate | 2016 |
| Mortgage Magnet Ltd | Financial services | 2014 |
| Mortgages and Life Limited | Financial services | 2019 |
| Mortgages Made Simple (Northampton) Limited | Financial services | 2022 |
| Mortimer Construction Services Ltd | Construction | 2017 |
| Mortimer-Hampson Ltd | Other services | 2025 |
| Morton Architectural Solutions Limited | Professional & scientific | 2014 |
| Morton Civils Ltd | Construction | 2014 |
| Morton Developments Ltd | Construction | 2014 |
| MOS Services MID Ltd | Construction | 2018 |
| MOS Traders Ltd | Wholesale & retail | 2021 |
| Mosaic Corporation Limited | Manufacturing | 1996 |
| Mosaic Limited | Construction | 2003 |
| Mosaic Professional (Trustees) LLP | | 2010 |
| Mosaic Professional Limited | Professional & scientific | 2003 |
| Mosaic Professional LLP | | 2008 |
| Mosaic Professional Tax Planning LLP | | 2010 |
| Mosaiko Limited | Real estate | 2018 |
| Mostafa Limited | Real estate | 2020 |
| Mosurveying Limited | Professional & scientific | 2017 |
| MOT Academy Ltd | Administrative & support | 2016 |
| MOT Agency Limited | Education | 2023 |
| MOT Compliance Group Limited | Professional & scientific | 2022 |
| MOT Consultancy Limited | Professional & scientific | 2022 |
| MOT Expert Limited | Education | 2015 |
| Motech Performance Limited | Administrative & support | 2015 |
| Mother Kellys Trading Ltd | Hospitality | 2018 |
| Motive Skateboards Ltd | Manufacturing | 2025 |
| Motive Transport Solutions Limited | Transport & logistics | 2020 |
| Motor City Performance Ltd | Wholesale & retail | 2022 |
| Motor Neurone Disease (Sales) Limited | Wholesale & retail | 1986 |
| Motor Neurone Disease Association | Health & social care | 1986 |
| Motor Racing Legends Ltd. | Arts & recreation | 2001 |
| Motordrivecraft Limited | Construction | 2025 |
| Motoro Limited | Wholesale & retail | 2025 |
| Motorsport Accountants Limited | Extraterritorial | 2013 |
| Motorsport Connector Ltd | Administrative & support | 2026 |
| Motorsport Focus Limited | Arts & recreation | 2013 |
| Motorsport Vehicle Preparation Limited | Professional & scientific | 2021 |
| Motus Partners Ltd | Administrative & support | 2026 |
| Moulton Allotments C.I.C. | Agriculture & fishing | 2016 |
| Moulton Autocare Limited | Wholesale & retail | 2026 |