| Mana OIL (UK) Co., Ltd. | Wholesale & retail | 2026 |
| Management Services to Hotels Limited | Administrative & support | 2011 |
| Managing Myself Ltd | Education | 2020 |
| Manahovi Ltd | Transport & logistics | 2022 |
| Manammanam Property Sourcing Ltd | Professional & scientific | 2019 |
| Manandhar Holdings Ltd | Real estate | 2025 |
| Manatan Ltd | Extraterritorial | 2025 |
| Manatu Limited | Administrative & support | 2021 |
| Manba Capital Ltd | Professional & scientific | 2021 |
| Manchetts Holdings Limited | Professional & scientific | 2000 |
| Manchetts Limited | Wholesale & retail | 2000 |
| Manchetts Property Ltd | Financial services | 2020 |
| Mancom Co., Ltd | Wholesale & retail | 2024 |
| Mandala Management Limited | Professional & scientific | 2021 |
| Mandarin Go Ltd | Education | 2018 |
| Mandarin IP Limited | Professional & scientific | 2021 |
| Manderston Clinical Services Limited | Professional & scientific | 2025 |
| Manderston Ltd | Real estate | 2023 |
| Mandeville Square (Saffron Walden) Management Company Limited | Households | 2004 |
| Mandy Lowton Tax Ltd | Professional & scientific | 2026 |
| Mangal Kashinath Limited | Real estate | 2022 |
| Mango Tree Properties Ltd. | Real estate | 2010 |
| Mangoes for Pears Ltd | Professional & scientific | 2026 |
| Mangudai Ltd | Information & communication | 2026 |
| Manhattan Place Crowthorne (Management) Limited | Households | 1981 |
| Maniac Mechanics Ltd | Wholesale & retail | 2019 |
| Manic Productions Limited | Arts & recreation | 2008 |
| Manifold Holding Ltd | Financial services | 2019 |
| Manifold Research Ltd | Information & communication | 2019 |
| Mann Technology Ltd | Professional & scientific | 2023 |
| Manna Housing Limited | Real estate | 2025 |
| Mannergrand Services Limited | Real estate | 1978 |
| Mannggo Limited | Wholesale & retail | 2025 |
| Manning Fruit Growers Ltd | Wholesale & retail | 2025 |
| Manningtree Park Residents Management Company Limited | Households | 2022 |
| Mano Healthcare Limited | Health & social care | 2025 |
| Manor Construction and Project Management Limited | Construction | 2021 |
| Manor Farm Dressage Ltd | Real estate | 2021 |
| Manor Farm Stretham LLP | | 2014 |
| Manor Green (Houghton) Management Company Limited | Households | 2018 |
| Manor Road Investments Limited | Real estate | 1979 |
| Manor Surveyors Home Surveys Ltd | Professional & scientific | 2024 |
| Manor Surveyors Limited | Professional & scientific | 2016 |
| Manqi Properties Limited | Real estate | 2013 |
| Manse Digital Consulting 2020 Ltd | Information & communication | 2020 |
| Manse Digital Consulting Ltd | Information & communication | 2017 |
| Mansell Court Residents Association Limited | Households | 1990 |
| Mansour DZ Limited | Hospitality | 2020 |
| Manta Design Ltd | Manufacturing | 2002 |
| Manta Software Limited | Information & communication | 1998 |
| Mantabright Limited | Real estate | 1988 |
| Mantle Tech Solutions Limited | Information & communication | 2024 |
| Manvara Limited | Wholesale & retail | 2022 |
| Manvi Clinical & IT Solutions Ltd | Information & communication | 2021 |
| Maoyun Co., Ltd | Extraterritorial | 2020 |
| MAP Life Sciences Limited | Professional & scientific | 2017 |
| MAP Patient Access Limited | Professional & scientific | 2012 |
| Mapair Thermography Ltd | Professional & scientific | 2017 |
| Maple & Crown Ltd | Wholesale & retail | 2025 |
| Maple Court Residents RTM Company Limited | Households | 2011 |
| Maple Facility Services Ltd | Construction | 2018 |
| Maple Paving & Groundworks Ltd | Professional & scientific | 2017 |
| Maple Soham Management Company Limited | Households | 2017 |
| Maplex Technology Ltd | Professional & scientific | 2023 |
| Maps Ltd | Professional & scientific | 2004 |
| Maput Limited | Real estate | 2020 |
| MAR Aircraft Services Ltd | Manufacturing | 2025 |
| MAR13TTT Ltd | Manufacturing | 2017 |
| Mara Base Ltd | Real estate | 2024 |
| Mara Care Limited | Health & social care | 2021 |
| Marais Consulting Ltd | Professional & scientific | 2023 |
| Maras Care Agency Ltd | Health & social care | 2023 |
| Maravedi Ltd | Administrative & support | 2023 |
| Marble Product Design Limited | Professional & scientific | 2011 |
| Marble Product Design Trustees Limited | Professional & scientific | 2024 |
| Marbloo Group Ltd | Professional & scientific | 2023 |
| March Chamber of Commerce Limited | Professional & scientific | 2005 |
| March Property Management Limited | Real estate | 2021 |
| March Tech Limited | Information & communication | 2015 |
| Marchand Watch Company Ltd | Manufacturing | 2015 |
| Marchbpgarage Ltd | Wholesale & retail | 2020 |
| Marchingdale Developments Limited | Construction | 2016 |
| Marchmont Place Management Company Limited | Households | 2006 |
| Marcin Boat Renovations Ltd | Manufacturing | 2023 |
| Marcjason Ltd | Other services | 2001 |
| Marco Engineering Shipping Service Co., Ltd | Wholesale & retail | 2023 |
| Marco Polo Network Ltd | Arts & recreation | 2011 |
| MARCON29 Ltd | Construction | 2024 |
| Mardale Aviation Ltd | Manufacturing | 2026 |
| Mareka Limited | Real estate | 1992 |
| Marfa Ltd | Administrative & support | 2017 |
| Marfield Court Limited | Real estate | 2006 |
| Margam Limited | Real estate | 1994 |
| Margaret's (Cambridge) Limited | Hospitality | 2023 |
| Margent Farm Limited | Agriculture & fishing | 2017 |
| Margreaves Ltd | Hospitality | 2016 |
| Maria 2019 Ltd | Manufacturing | 2025 |
| Maria Court Freehold Limited | Households | 1999 |
| Maria Court Property Management Co. Limited | Households | 1971 |
| Maria Massafrets Limited | Professional & scientific | 2024 |