| Moore Property Poole Ltd | Households | 2024 |
| Moore Tech Solutions Ltd | Information & communication | 2024 |
| Moorefitness Limited | Wholesale & retail | 2023 |
| Moorland View (SW) Development Limited | Construction | 2024 |
| Moortown Investments Limited | Real estate | 2016 |
| MOP Hair Limited | Other services | 2013 |
| Mor$$-Trans Ltd | Transport & logistics | 2025 |
| More Grey Solutions Limited | Transport & logistics | 2025 |
| More Than GAS Limited | Construction | 2010 |
| Moreau Consulting Ltd | Professional & scientific | 2019 |
| Morebetter Ltd | Information & communication | 2015 |
| Morello Mews Management Company Limited | Households | 2025 |
| Moremilk Limited | Information & communication | 2014 |
| Morgado Technologies Limited | Information & communication | 2026 |
| Morgan Commercial Southern Limited | Real estate | 2025 |
| Morgan Daniel Properties Holdings Ltd | Professional & scientific | 2023 |
| Morgan Daniel Properties Limited | Construction | 2015 |
| Morgan Properties (Holdings) Limited | Financial services | 2024 |
| Morgan Properties Southern Limited | Real estate | 2024 |
| Moriconium Group Ltd | Financial services | 2021 |
| Moriconium Holdings Ltd | Financial services | 2021 |
| Moriconium Investments Ltd | Financial services | 2026 |
| Moriyama Limited | Information & communication | 2006 |
| Morningside Estate Ltd | Agriculture & fishing | 2023 |
| Morningstar Development Limited | Arts & recreation | 2019 |
| Moro Cars Limited | Wholesale & retail | 2024 |
| Morph Technology Ltd | Information & communication | 2025 |
| Morris Bidco Limited | Financial services | 2021 |
| Morris Capital Investments Limited | Professional & scientific | 2022 |
| Morris Lane Ltd | Extraterritorial | 1998 |
| Morris Midco Limited | Financial services | 2021 |
| Morris Topco Limited | Financial services | 2021 |
| Morrish Builders (Poole) Limited | Construction | 1982 |
| Morrish Group Limited | Financial services | 2018 |
| Morrish Homes | Construction | 1982 |
| Mortara Consulting Ltd | Professional & scientific | 2026 |
| Mortec Holdings Limited | Financial services | 2024 |
| Mortec Welding & Fabrication Limited | Manufacturing | 2013 |
| Mortgage Rocket AI Ltd | Information & communication | 2026 |
| Morton Professional Services Limited | Health & social care | 2011 |
| Mortons Jewellers Limited | Wholesale & retail | 2014 |
| Morven Building Limited | Construction | 2022 |
| Morwell Estates Limited | Construction | 1998 |
| Moseysco Limited | Wholesale & retail | 2025 |
| Mosmotic Ltd | Information & communication | 2013 |
| Mosmotic Property Limited | Real estate | 2022 |
| MOT Car Repairs Ltd | Manufacturing | 2015 |
| Mote Software Ltd | Information & communication | 2023 |
| Motech Fleet Solutions LLP | | 2005 |
| Moth Mgmt Limited | Information & communication | 2025 |
| Moth Tattoo Limited | Wholesale & retail | 2021 |
| Mother Natura Ltd | Manufacturing | 2026 |
| Mothermind Ltd | Education | 2024 |
| Motion Aptitude Ltd | Information & communication | 2018 |
| Motion Construction & Joinery Ltd | Construction | 2019 |
| Motion LP | | 2023 |
| Motionlab Bags Ltd | Manufacturing | 2019 |
| Motionray Pictures Ltd | Information & communication | 2025 |
| Motivational and Personal Success Ltd | Education | 2019 |
| Motor Yachts International Limited | Transport & logistics | 2021 |
| Motorbiking Limited | Wholesale & retail | 2012 |
| Motorhome Dealer Group Ltd | Wholesale & retail | 2024 |
| Motorhome Marketplace Ltd | Wholesale & retail | 2021 |
| Motorsport Biomechanics Limited | Health & social care | 2017 |
| Motorway Ltd | Transport & logistics | 2025 |
| Motorwise Online Services Limited | Wholesale & retail | 2012 |
| Mouldcam Holdings Limited | Financial services | 2020 |
| Mouldcam Limited | Manufacturing | 2011 |
| Mount Blairy Management Company Limited | Households | 2015 |
| Mount Sushi Limited | Wholesale & retail | 2007 |
| Mountain Trail Investments Ltd | Real estate | 2024 |
| Moutza Global Ltd | Real estate | 2021 |
| Move Home Organisation CIC | Information & communication | 2026 |
| Movement Mediator Ltd | Other services | 2023 |
| Moverley Orthopaedics Ltd | Health & social care | 2020 |
| Mowana Properties Ltd | Real estate | 2026 |
| Mowowa Ltd | Wholesale & retail | 2025 |
| Moxey & Webb Limited | Construction | 2022 |
| Moyasta Homes Limited | Real estate | 2017 |
| MP Calibration (Properties) Limited | Real estate | 2014 |
| MP Carpentry South Limited | Manufacturing | 2018 |
| MP Media II Ltd | Wholesale & retail | 2019 |
| MPG 2018 Ltd | Real estate | 2018 |
| MPH Technical Consultancy Ltd | Professional & scientific | 2018 |
| Mpnn Investments Ltd | Financial services | 2025 |
| Mpower (UK) Management Consultancy Limited | Professional & scientific | 2004 |
| MPR Metal Design Limited | Manufacturing | 2008 |
| MPR Powder Coating Services Limited | Manufacturing | 2017 |
| MPS Building Ltd | Construction | 2006 |
| MPS Pashmina Ltd | Wholesale & retail | 2024 |
| MQR Associates Ltd | Information & communication | 2025 |
| MR Brooks Limited | Professional & scientific | 2026 |
| MR Gantt Ltd | Information & communication | 2022 |
| Mralextech Ltd | Information & communication | 2024 |
| MRD Architecture Ltd | Professional & scientific | 2020 |
| MRD Civil Engineering Ltd | Professional & scientific | 2022 |
| MRE Studio Limited | Professional & scientific | 2018 |
| MRF Fabrications (Southern) Limited | Manufacturing | 2009 |
| MRF Fabrications Limited | Manufacturing | 1997 |
| MRG Auto Repair Limited | Wholesale & retail | 2019 |