| MIA Building & Design Limited | Construction | 2024 |
| Michael Aubrey Barrow Limited | Professional & scientific | 2022 |
| Michael Aubrey Partnership Limited | Real estate | 1994 |
| Michael Barron Consulting Ltd | Professional & scientific | 2014 |
| Michael Hardy & Company (Lettings) Limited | Real estate | 1999 |
| Michael Hardy & Company (Wokingham) Limited | Real estate | 1984 |
| Michael Noone Limited | Construction | 2015 |
| Michael Youngs Bloodstock Consultancy Ltd | Agriculture & fishing | 2016 |
| Microchip Limited | Wholesale & retail | 1987 |
| Microchip Technology (UK) Holdings Ltd | Professional & scientific | 2018 |
| Microchip Touch Solutions Limited | Professional & scientific | 2016 |
| Midas Business Limited | Wholesale & retail | 2022 |
| Midas Theatre Ltd | Arts & recreation | 2022 |
| Middlesex Partnership Limited | Professional & scientific | 2012 |
| Mides Property Ltd | Real estate | 2024 |
| Midnight Bars a Ltd | Hospitality | 2026 |
| Midnight PUB a Limited | Hospitality | 2026 |
| Midnight PUB B Limited | Hospitality | 2026 |
| Mido Ltd | Information & communication | 2018 |
| Mignanelli Property Ltd | Real estate | 2018 |
| Miimis Limited | Hospitality | 2025 |
| Miko Laundrette Limited | Other services | 2026 |
| Mileswood Industrial Ltd | Real estate | 2024 |
| Mileswood Industrial Y2 Ltd | Real estate | 2026 |
| Military Aircraft Media Limited | Information & communication | 2022 |
| Mill Place Residents Management Company Limited | Households | 2006 |
| Millbank House Management Ltd | Households | 2024 |
| Millers of Wokingham Limited | Other services | 2024 |
| Millgate Court (Ruscombe) Management Company Limited | Real estate | 2005 |
| Milliner Financial Services Limited | Financial services | 2023 |
| Million Metre Challenge CIC | Health & social care | 2020 |
| Mills Investment Holdings Ltd | Financial services | 2023 |
| Mills Property Company Limited | Real estate | 2018 |
| Millside Management Limited | Households | 1996 |
| Millward, MAY & Co Limited | Professional & scientific | 2016 |
| Milne Enterprises Limited | Professional & scientific | 2014 |
| Milton Gardens Management (Wokingham) Co Limited | Real estate | 1970 |
| Milton Park Residents Management Company Limited | Households | 2016 |
| Minaa Limited | Real estate | 2021 |
| Mind 4 Mining Limited | Mining & quarrying | 2021 |
| Minden Business Services Ltd | Administrative & support | 2016 |
| Mindset Group Ltd | Health & social care | 2022 |
| Minegrange Limited | Real estate | 2000 |
| Mini GUP Property Limited | Real estate | 2024 |
| Minifycare Ltd | Wholesale & retail | 2024 |
| Mirkat Ltd | Wholesale & retail | 2024 |
| Misbourne Court Management Co. (Langley) Limited | Real estate | 1981 |
| Misdi Ltd | Construction | 2020 |
| Misfits Health Ltd | Manufacturing | 2016 |
| Miss Magic Ltd | Wholesale & retail | 2025 |
| Mission Health & Wellness Limited | Wholesale & retail | 2017 |
| Mitlee Limited | Wholesale & retail | 2025 |
| Mittal Technologies Limited | Information & communication | 2023 |
| Mitul Properties Ltd | Real estate | 2021 |
| Mixx Mktg Ltd | Professional & scientific | 2025 |
| Mizuno Corporation UK Limited | Manufacturing | 2021 |
| MJA Productions Ltd | Information & communication | 2024 |
| Mjmj Properties Ltd | Real estate | 2020 |
| MJN Construction Group Limited | Construction | 2024 |
| MJP Consulting Ltd | Wholesale & retail | 2025 |
| MK38 Group Limited | Professional & scientific | 2024 |
| MKJ & M.A Ltd | Transport & logistics | 2021 |
| MKJ Executive Ltd | Transport & logistics | 2025 |
| MLE Projects Ltd | Construction | 2018 |
| MLG Ventures Ltd | Real estate | 2026 |
| MLS Digital Technology Ltd | Information & communication | 2024 |
| MM Joshi Limited | Information & communication | 2009 |
| MMA Accountant Ltd | Professional & scientific | 2024 |
| MMV Consultancy Ltd | Information & communication | 2016 |
| Mmva Property Ltd | Real estate | 2026 |
| Mobile FOX Ltd | Other services | 2018 |
| Mobius at Work Limited | Professional & scientific | 2011 |
| Moda Investment Group Limited | Construction | 2022 |
| Modalis Intermodal UK Ltd | Manufacturing | 2025 |
| Modern Cars Ltd | Transport & logistics | 2023 |
| Modern Social Marketing Ltd | Professional & scientific | 2022 |
| Modish Tech PVT Ltd | Information & communication | 2025 |
| Mogaka Industries Ltd | Real estate | 2025 |
| Mohans PVT Ltd | Real estate | 2026 |
| Mokshavy Consulting Ltd | Information & communication | 2018 |
| Molecular Devices (UK) Limited | Professional & scientific | 1993 |
| Molly HCW Ltd | Other services | 2022 |
| Molly Maid Home Cleaning Services Limited | Administrative & support | 2017 |
| Molly Maid Investments Limited | Real estate | 2002 |
| Molly Maid UK Limited | Administrative & support | 2015 |
| Molly Millers Ltd | Administrative & support | 2025 |
| Momentum Sales Ltd | Professional & scientific | 2023 |
| Momentum Training Limited | Education | 2005 |
| Momhil Productions Limited | Information & communication | 2014 |
| Monamour LA Passion Ltd | Wholesale & retail | 2025 |
| Money Squirrel Ltd | Information & communication | 2023 |
| Moneymaximiser Ltd | Transport & logistics | 2008 |
| Monique Solutions Limited | Information & communication | 2011 |
| Monkey Mates Limited | Arts & recreation | 2003 |
| Monmax Finance Limited | Real estate | 2022 |
| Monmax Holdings Limited | Real estate | 2022 |
| Montague Park (Wokingham) Management Company Limited | Households | 2015 |
| Montpelier Apartments Ltd | Hospitality | 2021 |
| Montrose Developments ( Construction ) Ltd | Construction | 2022 |
| Montrose Developments Group Ltd | Construction | 2021 |